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PRINCIPLES   OF   SANITARY  SCIENCE 
AND   THE   PUBLIC   HEALTH 


14 


Principles  of  Sanitary  Science 
and  the  Public  Health 

WITH   SPECIAL   REFERENCE   TO 

THE   CAUSATION   AND   PREVENTION   OF 
INFECTIOUS   DISEASES 


BY 

WILLIAM  T.  SEDGWICK,  PH.D. 

PROFESSOR  OF  BIOLOGY  AND  i.2CTClCEii  u.:   SANITARY  SCIENCE  AND 

THE  PUBLIC  HEALTH    IN   THE   MASSACHUSETTS 'INSTITUTE  OF 

TECHNOLOGY,  BOSTON;    SOMETIME  BIOLOGIST  TO  THE 

STATE  BOARD  OF   HEALTH   OF  MASSACHUSETTS 


"With  all  deductions,  the  triumphs  of  sanitary  reform  as 
well  as  of  medical  science  are  perhaps  the  brightest  page  in 
the  history  of  our  century."  —  W.  E.  H.  LECKY 


THE   MACMILLAN   COMPANY 

LONDON :  MACMILLAN  AND  CO.,  LTD. 
1903 


COPYRIGHT,  1902, 
BY  THE  MACMILLAN  COMPANY. 


Set  up  and  electrotyped  April,  1902.    Reprinted  February, 
1903- 


Xortooofi 

J.  8.  Cuihing  *  Co.  —  Berwick  *  Smith  Co. 
Norwood,  M«M.,  IJ.S.A. 


Vv'/i 


TO 

State  ftoaro  of 
of 


FAITHFUL  THOUGH  UNPAID   GUARDIANS  OF  THE  PEOPLE 

IN  WHOSE  HONORABLE  SERVICE 

THE  AUTHOR   BEGAN  AN  ACQUAINTANCE  WITH  PUBLIC  HYGIENE 

AND    STRENGTHENED    A    LOVE    FOR    SANITARY    SCIENCE 

WHICH  HAVE  INCITED  HIM   TO  WRITE  THIS  BOOK 

AND  ESPECIALLY 
TO 

f^ntrg  ^irfterfag  OTalcott,  H.B.,  Cfjatttnan 

AND 

Jfrancis  iftUllg,  (£.!£.,  fEngmeer  ^Etnlier 

"Even  to  the  State's  best  health." 

—  TIMON  OF  ATHENS. 


PREFACE 

WITH  the  single  exception  of  the  change  effected  by 
the  acceptance  of  the  theory  of  organic  evolution,  there 
has  probably  been  no  modification  of  human  opinion 
within  the  nineteenth  century  more  wonderful,  or  more 
profoundly  affecting  the  general  conduct  of  human  life, 
than  that  in  our  attitude  toward  the  nature,  the  causation 
and  the  prevention  of  disease.  The  modern  conception 
of  the  living  body,  whether  plant  or  animal,  as  essentially 
a  physical  mechanism,  is  largely  the  result  of  discoveries 
in  the  domain  of  physics  and  chemistry  begun,  indeed, 
but  not  perfected,  before  the  recent  century.  The  mod- 
ern conception  of  disease  as  due  to  imperfection,  misbe- 
havior or  disturbance  of  a  physical  mechanism  depended 
for  its  development  on  an  acquaintance  with  the  physiology 
of  the  body  and  its  microscopic  structure  which  did  not 
exist  before  the  introduction,  in  the  third  decade,  of  the 
achromatic  objective.  The  microscopical  renaissance  which 
began  with  this  pregnant  invention  speedily  led  to  dis- 
coveries of  the  first  importance  in  the  normal  structure 
of  organized  bodies ;  disclosed  in  abnormal  tissues  the 
material  ravages,  and,  in  some  cases,  the  parasitic  origin 
of  disease ;  brought  into  full  view  a  flora  and  a  fauna  hith- 
erto unseen  or  only  half  seen ;  and,  by  the  end  of  the  fifth 
decade,  was  throwing  a  new  and  increasingly  powerful 
light  on  the  long-vexed  question  of  the  relation  of  fer- 
ments and  fermentation  to  decomposition,  putrefaction 
and  disease.  At  the  end  of  the  sixth  decade  a  new  theory 
of  infectious  disease  —  the  "germ"  theory  —  had  arisen, 


viii  PREFACE 

and  in  the  hands  of  Pasteur,  Lister  and  many  others  was 
already  bearing  fruit. 

The  last  quarter  of  the  century  has  witnessed  the  firm 
establishment  and  fruitful  development  of  these  several 
conceptions.  The  principal  theories  to  which  they  have 
given  birth  have  been  thoroughly  tested,  and  stand  to-day 
for  the  most  part  as  accepted  scientific  principles ;  while 
their  applications  to  the  practical  conduct  of  life  have 
everywhere  been  followed  by  results  of  extraordinary  in- 
terest and  importance.  Public  hygiene  and  state  medicine 
have  become  subjects  compelling  the  attention  of  states- 
men and  affecting  the  welfare  of  nations.'  Sanitary  law 
has  been  endowed  with  unusual  privileges  and  powers, 
and  sanitary  regulations  controlling  the  commerce  of  the 
civilized  world  are  debated  in  international  congresses. 
Sanitary  science  and  preventive  medicine,  terms  practically 
unknown  before  this  century,  have  become  almost  house- 
hold words.  Sanitary  arts  of  great  range  and  importance 
have  grown  up ;  vast  sums  are  annually  spent  for  private, 
and  especially  for  public,  sanitation ;  and  human  life  has 
been  made  safer,  longer  and  probably  happier. 

Standing  on  the  threshold  of  the  twentieth  century,  and 
surrounded  by  the  innumerable  municipal,  medical,  domes- 
tic, public  and  private  sanitary  safeguards  which  have 
already  sprung  from  these  discoveries  so  that,  in  spite 
of  facilities  for  the  spread  of  disease  by  the  development 
of  easy  international  transportation,  such  as  the  world  has 
never  before  known,  pestilences  and  plagues  are  no  longer 
greatly  dreaded,  it  is  hard  to  realize  that  our  not  very 
remote  ancestors  regarded  disease  as  an  insoluble  mystery, 
an  inscrutable  visitation  of  divine  Providence,  or  as  the 
penalty  and  consequence  of  sin.  Under  such  beliefs  there 
could  be  no  sanitary  science.  But  if  disease  be  disturb- 
ance of  a  physical  mechanism,  and  due  to  the  fact  that 
the  mechanism  is  made  of  poor  materials,  or  of  good  mate- 
rials badly  put  together,  or  that  it  is  badly  operated,  or 


PREFACE  ix 

that  it  is  interfered  with  by  unfavorable  environmental 
conditions,  it  becomes  easy  to  comprehend  at  least  ap- 
proximately the  causes  of  diseases,  and  in  many  cases  to 
remove  or  forestall  them.  It  is  precisely  this  which  the 
science  and  art  of  hygiene  seek  to  do,  namely,  to  compre- 
hend the  nature  of  the  human  body  and  its  diseases,  in 
order  as  far  as  possible  to  prevent  the  latter.  Hygiene  is 
the  science  and  art  of  the  conservation  and  improvement 
of  normal  living,  the  prevention  not  merely  of  premature 
death  but  of  abnormal  life ;  and  sanitary  science,  or  hygi- 
ology,  is  simply  the  body  of  scientific  doctrine,  or  the 
principles,  underlying  the  sanitary  arts. 

The  time  has  not  yet  come  for  a  scientific  treatise  on 
the  whole  subject  of  hygiene.  The  application  of  many  of 
the  results  of  experimental  science  to  the  welfare  of  man, 
extensive  and  valuable  though  they  are,  must  still  wait 
until  their  relations  to  everyday  life  become  clearer. 
Climatology,  clothing,  warming  and  ventilation,  foods  and 
feeding  are  subjects  undoubtedly  of  the  very  first  impor- 
tance, but  not  as  yet  reducible  in  their  relation  to  human 
life  to  simple  scientific  terms.  It  is  otherwise,  however, 
with  an  important  class  of  diseases  proceeding  from  the 
controllable  environment  and  known  as  "  communicable " 
or  "  infectious."  In  principle,  at  least,  these  are  now  well 
understood  and  capable  of  being  scientifically  dealt  with. 
Their  causes  are  known,  as  are  also  the  sources  in  which 
they  originate,  and  the  vehicles  by  which  they  are  trans- 
ported. Their  characteristic  operations  and  effects  are 
rapidly  becoming  familiar  everyday  facts.  Their  control, 
therefore,  in  theory  at  least,  becomes  easy  and  in  a  broad 
sense  a  problem  of  engineering,  which  subject  has  been 
defined  as  the  scientific  control  and  use  of  the  forces  and 
materials  of  nature  for  the  benefit  of  man.  So  much,  at 
least,  of  medical  or  sanitary  engineering  rests  upon  a  sound 
scientific  basis,  and  for  this  the  term  "  sanitary  science," 
as  distinguished  from  "  hygiene,"  may  conveniently  be 


X  PREFACE 

employed.  If,  hereafter,  our  knowledge  of  the  consti- 
tutional diseases,  and  the  ordinary  conduct  of  individual 
life,  comes  to  rest  upon  foundations  equally  sure,  simple 
and  scientific,  either  term  —  hygiene  or  sanitary  science  — 
may  be  dropped,  for  the  two  will  be  strictly  synonymous. 
Until  that  time  comes  it  will  probably  conduce  to  a  just 
recognition  of  the  real  situation  if  we  keep  the  term 
"  hygiene  "  more  as  an  end  to  be  sought  for  than  as  some- 
thing possessed,  and  endeavor  by  the  constant  extension 
of  the  boundaries  of  knowledge  and  the  application  of  the 
principles  of  science,  to  enlarge  the  field  of  sanitary  sci- 
ence until  its  boundaries  become  coterminous  with  those 
of  hygiene.  The  mutual  relations  of  hygiene,  sanitary 
science,  public  hygiene  and  personal  hygiene  are  dwelt 
upon  at  some  length  at  the  end  of  the  first  chapter,  and  to 
that  place  those  are  referred  who  care  to  pursue  this  sub- 
ject further. 

The  present  volume  is  the  direct  outgrowth  of  a  course 
of  lectures  on  Sanitary  Science  and  the  Public  Health 
given  for  several  years  by  the  author  to  certain  senior 
students — chiefly  engineers,  biologists,  chemists  and  archi- 
tects—  of  the  Massachusetts  Institute  of  Technology,  and 
it  has  been  prepared  primarily  for  their  use.  It  is  be- 
lieved, however,  that  a  larger  circle  of  students  and  some 
physicians,  publicists  and  general  readers  may  be  glad  to 
have  access  to  the  same  material.  If  any  apology  is 
required  for  the  occasional  use  of  examples  drawn  from 
the  author's  personal  experience,  chiefly  in  Massachusetts, 
it  may  be  said  that  these  have  been  referred  to,  not  because 
the  author  regards  them  as  of  paramount  importance,  but 
because  he  has  preferred  to  deal  as  far  as  possible  at  first 
hand  with  matters  within  his  own  knowledge  rather  than 
to  depend  upon  the  digests  or  even  the  original  reports  of 
others. 

It  must  not  be  forgotten  that  this  volume  deals  with  the 
principles,  rather  than  the  arts,  of  sanitation,  nor  that  it  is 


PREFACE  xi 

based  upon  lectures  given  to  beginners.  It  is  intended  to 
be  no  more  than  an  elementary  treatise  on  the  subject ; 
and  while  it  is  believed  that  it  contains  some  new  mate- 
rial, and  some  old  material  treated  from  new  points  of 
view,  no  special  claim  is  made  for  originality  either  in 
substance  or  in  method  of  presentation.  The  author  has 
chiefly  sought  to  bring  together  and  to  present  in  a  simple 
and  logical  form  those  fundamental  scientific  principles  on 
which  the  great  practical  arts  of  modern  sanitation  securely 
rest.  The  subject  is  so  vast  and  touches  human  welfare 
at  so  many  points  that  it  has  seemed  wise  to  omit  many 
things  altogether,  and  to  make  in  many  cases  only  brief 
and  summary  statements  where  more  extended  treatment 
would  have  been  easy  and  perhaps  desirable.  It  is  hoped, 
however,  that  clearness  and  accuracy  have  nowhere  been 
sacrificed  to  mere  condensation. 

The  author  has  prepared  the  present  work  in  the 
earnest  hope  that  it  may  find  a  useful  place  in  sanitary 
education,  both  professional  and  popular,  for  he  holds 
with  Lord  Derby  that  "  sanitary  instruction  is  even  more 
important  than  sanitary  legislation." 

THE  BIOLOGICAL  LABORATORIES, 

MASSACHUSETTS  INSTITUTE  OF  TECHNOLOGY, 

December,  1901. 


CONTENTS 

PART  I 

HEALTH  AND  DISEASE 
CHAPTER  I 

PACK 

ON  HEALTH,  OLD  AGE  AND  DISEASE.  ,  A  CLASSIFICATION  OF  DIS- 
EASES ACCORDING  TO  THEIR  PLACE/OF  ORIGIN.     DEFINITIONS       t         3 

The  Human  Mechanism  —  Old  Age  —  Death  and  its  Causes  — 
Disease,  not  Old  Age,  the  Principal  Nominal  Agent  of  Death  —  An- 
other View  of  the  Causes  of  Death  —  Intrinsic,  Constitutional  or 
Structural  Defects  of  the  Vital  Machinery  —  Intrinsic  or  Constitu- 
tional Diseases  —  Extrinsic  or  Environmental  Interferences  with  the 
Vital  Machinery  —  Extrinsic  or  Environmental  Diseases — The  Pre-  • 
vention  of  Constitutional  Disease  the  Special  Function  of  Personal 
Hygiene  —  Environmental  Diseases  more  readily  controlled — Their 
Prevention  the  Special  Function  of  Public  Hygiene — The  Pre- 
vention of  Premature  Death  the  Principal  Function  of  Hygiene 
and  Sanitation  —  Hygiene  and  Sanitary  Science  —  Definitions. 

CHAPTER  II 

K)N  ETIOLOGY  OR  THE  CAUSES  OF  DISEASE;   ANCIENT  AND  MODERN 
THEORIES.     THE  ZYMOTIC    (FERMENT)    OR  GERM  THEORY   OF 

INFECTIOUS  DISEASE 21 

The  Primitive  or  Daemonic  Theory — Theory  of  the  Four  Humors 
—  Roman,  Arabian  and  Mediaeval  Theories  —  Theory  of  Paracel- 
sus—  Physical  and  Chemical  Theories  —  Theory  of  Sydenham  — 
Theories  of  the  Eighteenth  Century  —  Influence  of  Haller  and 
Morgagni  —  Theory  of  Hahnemann  —  Theories  of  the  Nineteenth 
Century  —  The  Germ  Theory  of  Fermentation  —  The  Zymotic  or 
Germ  Theory  of  Infectious  Disease  —  Louis  Pasteur  and  Infectious 
Diseases  of  Silkworms — Joseph  Lister  and  Infectious  Diseases  of 
Wounds  —  Sanitary  (Aseptic)  Surgery  the  First  Fruit  of  the  Germ 
Theory. 


xiv  CONTENTS 

CHAPTER  III 

PAGE 

ON  THE  RISE  AND  INFLUENCE  OF  BACTERIOLOGY.  TRANSFORMATION 
OF  THE  ZYMOTIC  INTO  THE  ZYMOTOXIC  THEORY  OF  INFECTIOUS 
DISEASE 46 

The  Achromatic  Objective — Animalcula,  Vibrionia,  Bacteria — 
The  Beginnings  of  Bacteriology  —  Its  Foundations  securely  laid  by 
Louis  Pasteur  —  Robert  Koch  proves  that  Micro-organisms  are  the 
Cause  and  not  merely  the  Consequence  of  Splenic  Fever  —  Photo- 
graphs and  Spores  of  Bacteria  —  A  New  Method  for  Bacterial  Cul- 
tivation —  Establishment  of  Bacteriology  as  a  Science  by  Koch  in 
1881 — Quick  Discovery  by  its  Aid  of  the  Germs  of  Tuberculosis, 
Typhoid  Fever,  Asiatic  Cholera,  Diphtheria  and  Tetanus  —  How 
precisely  do  Germs  produce  Disease  ?  —  Sepsins,  Ptomaines  and 
Toxins  —  Transformation  of  the  Zymotic  Theory  of  Infectious  Dis- 
ease into  the  Zymotoxic  Theory  of  To-day  —  Objections  to  the 
Germ  Theory. 

CHAPTER  IV 

SANITARY  ASPECTS  OF  THE  STRUGGLE  FOR  EXISTENCE.  PARASITISM. 
HEALTH  AND  DISEASE  IN  TERMS  OF  GENERAL  BIOLOGY.  VITAL 
RESISTANCE,  SUSCEPTIBILITY  AND  IMMUNITY  ....  62 

Sanitary  Aspects  of  the  Struggle  for  Existence  —  The  Parable  of 
the  Sower  —  Parasitism  and  Infectious  Disease  —  Parasites  and 
their  Hosts — The  Germ  Theory  a  Theory  of  Parasitism  —  Materies 
morbi  —  The  Lifeless  Environment  and  Disease  —  Organisms  and 
their  Environments  —  Health  and  Disease  in  Terms  of  General 
Biology  —  Three  Principal  Sanitary  Conditions  or  States  of  Relation 
— Their  Practical  Importance  —  Sanitary  Paradoxes  —  Vital  Resist- 
ance —  Susceptibility  —  Immunity  —  Inoculation  for  Small-pox  — 
Jenner  and  Vaccination —  Pasteur  and  Attenuation —  Metschnikoff 
and  Phagocytosis  —  Behring  and  Antitoxic  Serums  —  Serum  as 
Cure  and  Serum  as  Prevention  —  Summary. 


CONTENTS  xv 


PART   II 

INFECTION  AND  CONTAGION:  THEIR  DISSEMINA- 
TION AND  CONTROL.  FUNDAMENTAL  PROB- 
LEMS OF  PUBLIC  SANITATION 

CHAPTER  V 

FACE 

ON  INFECTION  AND  CONTAGION  :  THE  PATHS  AND  PORTALS  BY  WHICH 
THEY  ENTER  THE  BODY;  THE  RESISTANCE  WHICH  IT  OFFERS;  THE 
VEHICLES  BY  WHICH  THEY  ARE  CONVEYED;  AND  THE  PLACES  OF 
THEIR  ORIGIN.  ANIMALS  AND  THEIR  EXCRETA  AS  SOURCES  AND 
PRIME  MOVERS  OF  INFECTION 89 

The  Meaning  of  "  Infection  "  —  The  Skin  and  Epithelia  as  Struc- 
tural Defences  of  the  Living  Body  against  the  Invasions  of  Disease 

—  "  The  Solution  of  Continuity  "  —  Infection  by  Way  of  the  Skin 

—  Wounds  and  the  Diseases  of  Wounds  —  Tetanus  or  "Lockjaw" 

—  Insects  as  Vehicles  —  Mosquitoes  and  Malaria,  Yellow  Fever, 
etc.  —  Flies  and  Typhoid  Fever  —  Infection  by  Way  of  the  Ali- 
mentary, Pulmonary   and    Genito-urinary  Tracts  —  Toxins    again 
— The  Physiological  Defences  of  the  Living  Body  —  "Vital  Re- 
sistance"—  "Susceptibility"    and   "Immunity"  —  The    Precise 
Meaning  of  "  Contagion  "  —  Personal  Contact  (Contagion)  vs.  In- 
fection and  their  Relative  Efficiency  in  the  Distribution  of  Disease 

—  Man    and  Other   Animals    the    Principal    Primary  Sources   of 
Infection  —  Man  and  Other  Animals  and  especially  their  Excreta 
its  Principal  Primary  Vehicles  —  Earth,  Air,  Water  and  Animals 
(Insects,  etc.)  the  Principal  Secondary  Vehicles  of  Infectious  Dis- 
ease. 

CHAPTER  VI 

ON  DIRT  AND  DISEASE.  THE  LIVING  EARTH.  DIRT,  DUST  AND  AIR 
AS  VEHICLES  OF  INFECTION.  FILTH  AND  FILTH  DISEASES  AND  THE 
PHILOSOPHY  OF  CLEANNESS 108 

Precise  Meaning  of  the  Terms  "Dirt,"  "  Earth,"  "  Soil,"  "  Dust," 
etc.  —  Their  Popular  Significance  as  derived  from  Experience  — 
Clean  Earth  vs.  Dirty  and  Infectious  Earth  —  Modern  Ideas  of  a 
Living  Earth  —  Earth  as  a  Vehicle  of  Disease  —  Tetanus  —  Dust  as 
a  Vehicle  —  Its  Dangers — The  Atmosphere  as  a  Vehicle  of  Disease; 
Ancient  and  Modern  Theories  —  Pestilential  Vapors;  Atmospheric 
Influences;  Miasmata  —  Microbes  of  the  Air — Filth  and  Filth 
Diseases  —  The  Pythogenic  Theory  —  Modern  Views  of  Filth  and 
Disease  —  The  Philosophy  of  Cleanness  —  Personal  vs.  Public 


xvi  CONTENTS 

FAGS 

Cleanness  —  Public  Drinking  Cups,  Towels,  Razors,  etc.,  and  their 
Dangers — The  Disposal  of  Dirt,  Dust,  Garbage  and  Refuse  — 
Cleanliness  —  Its  Aseptic  and  Antiseptic  Value. 

CHAPTER  VII 

ON  SEWAGE  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE  :  ITS  PROPER  Dis- 
>  POSAL  AND  PURIFICATION;  THE  NATURAL  PURIFICATION  OF  SEW- 

AGE BY  FERMENTATION  AND  THE  LIVING  EARTH  .        .        .        .123 

The  Genesis  and  Composition  of  Sewage  —  Its  Dangerous  Ele- 
ments and  Properties  —  The  Importance  of  its  Sanitary  Disposal  — 
Primitive  Methods  of  Disposal  —  Modern  Methods  —  Disposal  and 
Purification  by  Dilution  —  Disposal  in  Rivers  —  "The  Self- Purifica- 
tion" of  Streams — Disposal  in  Lakes — Disposal  in  Harbors,  Estu- 
aries and  the  Sea  —  Principles  involved  in  these  Cases  —  Disposal 
and  Purification  on  Land  —  The  Living  Earth  —  Intermittent  Fil- 
tration—  Experiments  in  England  —  In  Massachusetts — The  Law- 
rence Experiment  Station — Theory  of  Intermittent  Filtration  — 
A  Bio-chemical  Process  —  Objections  to  Intermittent  Filtration  — 
Disposal  of  Sewage  by  Irrigation  —  Sewage  Farms  —  Objections 
to  Sewage  Disposal  by  Irrigation  and  Sewage  Farming  —  Disposal 
and  Partial  Purification  of  Sewage  by  Chemical  Precipitation  —  By 
Electricity  —  By  Fermentation  or  Putrefaction  —  Fate  of  the  Infec- 
tious Materials  in  the  Disposal  and  Purification  of  Sewage  —  Sew- 
age Fields  and  Sewage  Filters  as  Bacterial  Tombs. 

CHAPTER  VIII 

VON  WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE.    THE  POLLUTION 
OF  PUBLIC  WATER  SUPPLIES.      NOTABLE    EPIDEMICS    DUE    TO 

INFECTED  DRINKING  WATER 164 

Drinking  Water  as  a  Vehicle  of  Disease  —  Diarrhoeal  Diseases 
and  Drinking  Water  —  Typhoid  Fever  and  Asiatic  Cholera  —  An 
Epidemic  of  Asiatic  Cholera  traced  to  a  Polluted  and  Infected  Well : 
the  Case  of  the  Broad  Street  (London)  Pump  —  An  Epidemic  of 
Asiatic  Cholera  in  London  in  1866  traced  to  an  Infected  Public 
Surface-water  Supply  —  An  Epidemic  of  Typhoid  Fever  in  Lausen 
^Switzerland)  traced  to  an  Infected  Public  Ground-water  Supply  — 
An  Epidemic  of  Typhoid  Fever  in  Caterham  (England)  traced  to 
a  Polluted  Ground-water  Supply  —  An  Epidemic  of  Typhoid  Fever 
in  Plymouth  (Pennsylvania)  traced  to  a  Polluted  Surface-water 
Supply  —  Typhoid  Fever  in  Lowell,  Lawrence  and  Other  Cities  on 
the  Merrimac  River —  Pollution  vs.  Infection  —  The  Case  of  New- 
buryport  (Mass.)  —  An  Epidemic  of  Asiatic  Cholera  in  Hamburg 


CONTENTS  xvii 

PAGE 

(Germany)  traced  to  an  Infected  Surface-water  Supply  —  An  Epi- 
demic of  Typhoid  Fever  in  New  Haven  (Conn.)  traced  to  an 
Infected  Surface-water  Supply  —  Diseases  Other  than  Typhoid 
Fever  and  Asiatic  Cholera  traced  to  Polluted  Drinking  Waters  — 
Dysentery  and  Diarrhoea  —  Concluding  Remarks  on  Drinking 
Water  as  a  Vehicle  of  Disease. 

CHAPTER  IX 

'  ON  THE  ESTABLISHMENT  AND  CONSERVATION  OF  PURITY  IN  PUBLIC 

WATER  SUPPLIES 221 

Public  Supplies  as  Public  Dangers — The  Atmosphere  as  the  Source 
of  Water  Supply  —  The  Pollution  of  Rain  Water  and  of  Snow  by 
Dust  —  Influence  of  the  Earth  upon  the  Purity  of  Rain  Water  — 
"  The  Living  Earth "  again  —  Ground-waters  and  their  Pollution 
and  Purification  —  The  Conservation  of  Purity  in  Ground  Waters; 
Microscopical  Organisms  and  Noxious  Tastes  or  Odors  —  Surface 
Waters  and  their  Pollution  —  "The  Self-purification  of  Streams" 
once  more  —  Quiet  Water  rather  than  Running  Water  purifies 
itself — Natural  Processes  of  Water  Purification  —  Purification  by 
Storage  —  By  Slow  Sand  Filtration  —  Artificial  Processes  of  Water 
Purification  —  Rapid  Mechanical  Filters  —  Conservation  of  Purity 
in  Surface  Waters  —  Recapitulation  —  Protection  by  Statute  of  the 
Purity  of  Inland  Waters  in  Massachusetts  —  Sanitary  Protection  of 
Public  Water  Supplies  —  Advanced  Legislation  —  Sanitary  Inspec- 
tion and  Protection  of  Watersheds  —  Expert  Supervision  an  Abso- 
lute Requirement  of  Sanitary  Science. 

CHAPTER  X 

'ON  ICE  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE.    THE  POLLUTION  OF 

ICE.    ICE  SUPPLY  AND  THE  PUBLIC  HEALTH        .        .        .        .251 

The  Use  of  Ice  in  Drinks  —  Does  Polluted  Water  purify  itself  in 
Freezing  ?  —  Epidemics  charged  to  Infected  Ice  —  Investigations 
of  the  Purity  of  Ice  by  Various  Observers  —  Ice  as  a  Vehicle  of 
Infectious  Disease  —  The  Pollution  of  Ice  —  General  Inferences 
and  Conclusions. 

CHAPTER  XI 

ON  MILK  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE.  THE  POLLUTION 
AND  INFECTION  OF  MILK.  EPIDEMICS  TRACED  TO  INFECTED 
MILK.  MILK  SUPPLY  AND  THE  PUBLIC  HEALTH  .  .  .  263 

Milk  as  Food  for  Microbes  and  Mankind  —  The  Modern  Dis- 
trust of  Uncooked  Milk  —  Its  Origin  in  Epidemics  traced  to  Milk 
—  The  Fermentations  of  Milk  —  Normal  vs.  Fermented  Milk  — 


xviii  CONTENTS 

PAGE 

Infantile  Diarrhoea  and  Cholera  Infantum  —  The  Pollution  of  Ordi- 
nary Milk  —  Various  Systems  of  Public  Milk  Supply  in  Villages, 
Cities,  etc.  —  Milk  Supply  in  Warm  Countries — Epidemics  of  Ty- 
phoid Fever  in  Massachusetts  traced  to  Infected  Milk  Supplies  — 
Epidemics  of  Typhoid  Fever  traced  to  Skimmed  Milk  and  Cream- 
eries— The  Question  of  Tuberculosis  in  Milk  —  Scarlet  Fever  and 
Diphtheria — The  Protection  of  Milk  Supplies  from  Pollution  — 
Their  Protection  from  Infection  —  Safeguards  against  Polluted  and 
Infected  Milk  —  Sterilization  —  Pasteurization  —  Condensation  — 
Modification  —  Model  Dairies  —  The  Outlook  for  Improved  Milk 
Supplies. 


CHAPTER  XII 

ON  CERTAIN  UNCOOKED  FOODS  (MEATS,  OYSTERS,  FRUITS,  VEGETA- 
BLES, ICE  CREAMS,  ETC.)  AS  VEHICLES  OF  INFECTIOUS  DISEASE. 

THE  SANITARY  SIGNIFICANCE  OF  COOKERY 293 

An  Infectious  Disease  (Trichinosis)  produced  by  Microscopic 
Worms  in  Raw  Pork —  Trichina  spiralis  —  The  Question  of  Infec- 
tion by  Tuberculous  Meat  —  Raw  Oysters  as  a  Vehicle  of  Disease 
—  An  Epidemic  of  Typhoid  Fever  traced  to  Infected  Oysters  — 
English  and  French  Opinion  in  Regard  to  Dangers  from  Raw  Shell- 
fish — The  Contamination  of  Oyster  Beds  by  Sewers  —  Fruits,  Vege- 
tables, Ice  Creams,  etc.,  as  Vehicles  of  Disease  —  The  Sanitary 
Significance  of  Cookery. 

CHAPTER  XIII 

ON  THE  PREVENTION  AND  INHIBITION  OF  INFECTION,  DECOMPOSITION 

AND  DECAY.    ASEPSIS  AND  ANTISEPSIS 311 

Asepsis,  or  the  Prevention  of  Infection  by  Exclusion — Quaran- 
tine—  Isolation  —  Immunity,  or  the  Prevention  of  Infection  by 
Insusceptibility  —  Inoculation  —  Vaccination  —  Progress  in  Vacci- 
nation due  to  the  Labors  of  Pasteur  —  A  Public  Demonstration  of 
Protective  Inoculation  or  "  Vaccination  "  for  Anthrax  —  Antisepsis, 
or  the  Inhibition  of  Infection  by  Antiseptics  —  Antiseptics  and  the 
Theory  of  their  Action  — The  Control  of  Infection,  Decomposi- 
tion and  Decay  —  Intestinal  Antisepsis  —  Sanitary  Aspects  of  Re- 
frigeration and  Cold  Storage  —  Of  Desiccation  (Drying,  Evapora- 
tion) —  Of  Smoking  —  Of  Preserving  —  Of  Canning  —  Of  Pickling 
—  Of  Pasteurizing  —  Of  Condensing. 


CONTENTS  Xix 

CHAPTER  XIV 

PAGE 

ON  THE  DESTRUCTION  OR  REMOVAL  OF  INFECTION  —  DISINFECTION 

AND  DISINFECTANTS 334 

Definitions  —  Disinfection  by  Chemical  Agencies  —  Fire,  Poisons, 
etc.  —  By  Physical  Agencies  —  Heat,  Cold,  Dryness,  Light, 
Electricity,  etc.  —  By  Mechanical  Means  —  Filtration,  Sedimenta- 
tion, etc.  —  By  Biological  Agencies  —  Starvation,  Old  Age,  "  Un- 
favorable Environments,"  etc.  —  The  Problem  of  Disposal  of  the 
Dead  —  Interment  vs.  Cremation  —  Special  Disinfectants  —  Germi- 
cidal-efficiency  Tests  —  Present  State  of  the  Art  —  Intestinal  Disin- 
fection. 


APPENDIX 

ON  SOME  POPULAR  BELIEFS  AS  TO  CERTAIN  SPECIAL  AND  PECULIAR 

CAUSES  OF  DISEASE 347 

The  Belief  in  Dangers  from  Sewer  Gas  —  The  Belief  in  Dangers 
from  Well  Water  —  The  Belief  in  Dangers  from  Broken  Drains  — 
The  Belief  in  Dangers  from  Bad  Smells  — The  Belief  that  Con- 
sumption is  Inherited  and  therefore  a  Constitutional  Disease  —  The 
Probable  Truth  about  Endemic  Disease — The  Belief  in  Dangers 
from  Atmospheric  and  Telluric  Disturbances — The  Belief  in  Dan- 
gers from  Damp  Cellars — The  Belief  in  Dangers  from  Human 
Breath  —  The  Probable  Truth  about  Disease  from  Putrefaction  and 
Decay  —  From  Spoiled  Meats  —  From  Ice  Cream  Poisoning  — 
From  Canned  Foods. 


PART   I 

HEALTH  AND  DISEASE 


SANITARY  SCIENCE  AND  THE 
PUBLIC  HEALTH 


/  2  1  7  7 

ON  HEALTH,  OLD  AQE  AND  DISEASE.  A  CLASSIFICATION 
OF  DISEASES  ACCORDING  TO  THEIR  PLACE  OF  ORIGIN. 
DEFINITIONS 

"  The  fundamental  conception  of  the  living  body  as  a  physical 
mechanism  ...  is  the  distinctive  feature  of  modern  as  contrasted 
with  ancient  physiology."  —  HUXLEY. 

"To  die  of  age,  is  a  rare,  singular  and  extraordinarie  death." 
—  MONTAIGNE. 

§  i.  —  The  Human  Mechanism 

WE  must  endeavor  to  obtain  at  the  outset  clear  ideas  of 
what  is  meant  by  the  words  "  health  "  and  "  disease,"  which, 
to  physiologists  at  least,  are  terms  of  precise  and  definite 
meaning  indicating  actual  states  or  conditions  of  the  living 
body.  A  moment's  consideration  will  show  that  it  is  essen- 
tially no  more  difficult  to  comprehend  the  idea  of  a  general 
state  or  condition  of  a  living  body  than  a  general  state  or 
condition  of  a  lifeless  body,  such  as  a  stone  or  a  piece  of 
iron  or  a  watch  or  a  locomotive. 

Closely  examined,  the  living  body  reveals  itself  as  a 
machine  or  mechanism  composed  of  parts  (called  organs) 
precisely  as  a  watch  does.  Very  much  in  the  same  sense 
that  a  watch  is  a  time-piece  a  living  body  is  a  life-piece. 
If  a  watch  appears  to  be  in  good  order  and  running  well, 

3 


4  HEALTH,   OLD   AGE   AND   DISEASE 

we  say  that  it  is  a  good  and  normal  time-piece.  So  also  if 
the  human  body  appears  to  be  in  good  order  and  working 
well,  we  call  it  a  normal  or  healthy  body ;  but  if  it  be  out 
of  order  and  not  working  well,  we  say  that  it  is  in  a  state 
of  "  disease,"  either  temporary  or  permanent.  In  a  word, 
health  is  the  normal,  and  disease  the  abnormal,  condition 
of  the  living  mechanism.  Nor  is  this  a  mere  analogy  or 
abstraction.  To  the  biologist  it  calls  up  a  picture  —  the 
picture  of  health  or  the  picture  of  disease.  For  precisely 
as  the  experienced  watchmaker  carries  in  his  mind's  eye 
and  can  at  any  moment  summon  up  a  mental  image  of 
intricate,  correlated  and  interdependent  parts  —  springs, 
wheels,  bearings  —  lying  concealed  within,  but  which,  taken 
together  and  in  a  certain  definite  and  orderly  relation  one 
to  another,  make  up  the  works  of  a  delicately  adjusted 
chronometer  in  actual  operation,  and  constitute  a  valuable 
time-keeper;  so  the  physiologist,  familiar  with  bones, 
muscles  and  nerves,  with  g&od  red  blood  and  beating 
heart,  all  cooperating  to  a  common  end,  —  the  healthy, 
normal  life  of  the  organism,  —  can  summon  up  at  will  the 
picture  of  normal,  vigorous,  almost  superfluous  vitality  in 
some  vascular  life-keeper.  And  in  one  sense,  hardly  more 
wonderful  to  him  is  the  pulsing,  vibrant,  living  mechanism 
than  to  the  jeweller  the  accurate  chronometer  of  delicate 
adjustment.  To  the  savage  the  watch  would  be  incompre- 
hensible and  inexplicable.  And  so  to  others  than  physi- 
ologists the  living  body  seems  something  altogether  strange 
and  wholly  apart. 

The  student  of  sanitary  science  must  take  up  the  physi- 
ologist's point  of  view.  He  must  look  upon  the  living 
body  as  a  mechanism ;  a  mechanism  of  curious  origin  and 
history  and  of  marvellous  complexity ;  the  most  wonder- 
ful of  all  machines ;  one  before  which  the  wisest  of  men 
stands  very  much  as  does  the  savage  before  the  chro- 
nometer, ignorant  of  its  origin,  ignorant  of  its  ultimate 
construction,  ignorant  of  its  fate;  but  yet  unlike  the 


THE   HUMAN   MECHANISM  5 

savage  because  without  superstition  and  without  fear; 
knowing  that  the  body  is  nevertheless  a  mechanism,  sub- 
ject to  natural  laws,  and  with  all  its  parts  cooperating  to 
one  end,  —  the  lif e-keeping  function  of  the  whole.  The 
living  body  is  like  a  machine,  also,  in  that  it  receives  all 
its  energy  from  without  and  is  merely  a  transformer  of 
energy ;  in  that  it  is  profoundly  sensitive  (as  is  a  watch) 
to  its  environment  —  to  heat,  to  cold,  to  mechanical  inju- 
ries. This  living  machine  may  be  well  built  or  ill ;  of 
good  timber  or  poor;  it  may  be  sound  and  flawless  or 
defective  in  construction.  These  are  accidents  of  birth 
or  ancestry;  effects  of  good  feeding  or  bad,  of  normal 
living  or  abnormal. 

§  2.  —  The  Making  of  the  Body,      Youth  and  Maturity 

Unlike  the  watch,  the  living  mechanism  is  not  made,  but 
grows.  With  the  fusion  of  two  unlike  cells  —  ovum  and 
spermatozoon  —  the  life  of  the  individual  begins.  Hence- 
forward its  increase  in  size,  its  acquirement  of  organs  and 
tissues,  its  powers  and  properties,  are  due,  not  as  in  the 
making  of  a  watch  to  the  assembling  and  cooperation  of 
parts  already  perfected,  but  to  processes  of  its  own,  to  cell 
growth,  cell  multiplication,  cell  differentiation  —  balanced, 
adjusted,  directed  and  controlled  chiefly  from  within. 
The  first  portion  of  this  development  takes  place  within 
the  body  of  the  parent,  and  is  called  intra-uterine  or 
embryonic  life ;  the  second  is  a  helpless  state  outside  the 
body,  but  under  parental  care,  the  period  of  infancy ;  a 
third,  somewhat  less  dependent  but  ill-defined,  is  the 
period  of  childhood  and  adolescence.  These  three  periods 
—  the  periods  of  youth  —  ripen  into  adult  life  or  maturity, 
and  this  passes  on  into  old  age.  Only  very  rarely  does 
the  mechanism  last  longer  than  a  century.  Usually,  long 
before  this  it  has  stopped  in  death,  which  may  have  marked 
the  end  of  life  at  birth,  or  even  long  before  it,  in  infancy, 


6  HEALTH,  OLD  AGE  AND   DISEASE 

in  childhood,  in  maturity  or  in  age.  The  period  of  growth 
and  the  period  of  decline  —  infancy  and  old  age  —  appear 
to  be  the  periods  when  death  is  least  successfully  resisted. 
As  has  been  finely  said :  "  In  this  last  respect  the  two  ex- 
tremes of  life  resemble  one  another.  The  freshly  lighted 
taper  and  that  which  is  burnt  down  to  the  socket  are  both 
easily  extinguished  by  the  slightest  puff  of  wind."  ! 

§  3-  —  Old  Age 

Finally  the  living  mechanism  may  wear  out  —  it  must 
wear  out.  No  machine,  however  perfect,  can  run  or  be 
run  forever.  However  smooth  its  bearings,  however  per- 
fect its  adjustments,  dust  and  friction,  and  wear  and  tear, 
do  their  work,  and  in  time  the  machine  becomes  old.  So, 
also,  is  it  with  the  human  mechanism.  No  matter  how 
well  cared  for,  or  how  cleverly  managed,  old  age  finally 
creeps  over  it ;  the  rust  of  rheumatism  gathers  in  its  joints; 
its  bearings  grow  eccentric ;  its  movements  irregular  and 
halting;  until  by  and  by  something  breaks,  and  death 
stops  the  whole  machinery.  Death  is  the  final  stoppage 
of  the  living  mechanism.  But  while  theoretically  this 
comes  only  when  all  parts  are  worn  out,  and  as  the 
simple,  natural  cessation  of  function  from  sheer  and  gen- 
eral debility  of  each  and  every  organ,  it  does  not  in  fact 
come  very  often  in  this  way.  The  machine  breaks  down ; 
it  does  not  wear  out.  Some  organ  or  part  gives  out 
comparatively  early,  and  by  failure  to  do  its  part  destroys 
the  whole. 

Facts  like  these  may  or  may  not  have  inspired  the  author 
of  the  "  One-Hoss  Shay,"  who,  in  his  famous  poem  has 
described  the  building  of  the  body ;  its  defects  of  consti- 
tution and  construction ;  the  ordinary  causes  of  its  death ; 
and,  finally,  the  theoretic  possibility  of  so  making  a  living 
body  that  it  shall  die  at  last  only  because  it  is  worn  out, 

1  P.  H.  Pye-Smith,  "  Lumlcian  Lectures,"  London,  1892. 


A   PHYSIOLOGICAL  ALLEGORY  7 

namely,  from  old  age.  In  the  person  of  the  deacon  the 
Autocrat,  himself  a  physiologist,  has,  consciously  or  uncon- 
sciously, stated  the  case  as  follows  :  — 

"Now  in  building  of  chaises,  I  tell  you  what, 
There  is  always  somewJiere  a  weakest  spot,  — 
In  hub,  tire,  felloe,  in  spring  or  thill, 
In  panel,  or  cross-bar,  or  floor,  or  sill, 
In  screw,  bolt,  thoroughbrace,  —  lurking  still, 
Find  it  somewhere  you  must  and  will,  — 
Above  or  below,  or  within  or  without,  — 
And  that's  the  reason,  beyond  a  doubt, 
A  chaise  breaks  down,  but  doesn't  wear  out" 

His  remedy  for  this  unfortunate  state  of  things  was,  — 

"  only  jest 
T'  make  that  place  uz  strong  uz  the  rest." 

Accordingly  the  deacon  proceeded  to  build  his  master- 
piece in  such  a  way  that  — 

"  The  wheels  were  just  as  strong  as  the  thills, 
And  the  floor  was  just  as  strong  as  the  sills, 
And  the  panels  just  as  strong  as  the  floor, 
And  the  whippletree  neither  less  nor  more, 
And  the  back  cross-bar  as  strong  as  the  fore, 
And  spring,  and  axle  and  hub  encore"  — 

with  the  result  that  after  a  whole  century  of  life  though 
there  were  indeed 

..."  traces  of  age  in  the  one-hoss  shay, 
A  general  flavor  of  mild  decay," 
there  was 

"  nothing  local  as  one  may  say  !  " 

And  when  the  end  came  from  sheer  old  age,  — 

..."  it  went  to  pieces  all  at  once  — 
All  at  once,  and  nothing  first  — 
Just  as  bubbles  do  when  they  burst." 

Such  is  old  age:  the  low-burning  flame,  which  flickers 
and  finally  goes  out ;  the  ripened  fruit,  which  drops  heavily 
to  earth;  the  old  mechanism,  which  after  long  years  of 


8  HEALTH,  OLD  AGE  AND  DISEASE 

service  finally  refuses  to  work,  simply  because  it  is  worn 
out.  All  this  is  the  natural  and  ordinary  course  of  life. 
With  this  sanitary  science  has  but  little  to  do  except  to 
exercise  a  wholesome  supervision  and  watchfulness  and  to 
provide  the  most  favorable  environment  possible.  With 
ordinary  breakdowns  from  defects  in  the  machine  itself, 
in  its  construction,  or  its  operation,  sanitary  science  has  also 
little  if  anything  to  do.  Good  stock  comes  by  inheritance 
not  by  manufacture,  as  truly  in  men  as  in  timber.  Men 
do  not  gather  grapes  from  thorns  or  figs  from  thistles. 
Neither  do  strong  constitutions,  as  a  rule,  spring  from 
weak  ancestors  or  good  lungs  from  tuberculous  parentage. 

§  4.  —  Death  and  its  Causes 

Life  is  the  period  of  activity  of  the  vital  mechanism. 
Death  marks  the  final  stoppage  of  that  machinery.  Life 
is  a  perpetual  struggle  of  the  organism  with  its  environ- 
ment. Death  marks  its  final  and  unconditional  surrender. 
In  the  higher  forms  of  life  death  is  the  natural  and  inevi- 
table end  of  life.  Old  age  marks  the  approach  of  death 
and  is  not  less  natural  and  inevitable.  Doubtless  the 
principal  cause  of  death  should  be  old  age,  the  natural 
maturity  of  the  organism,  the  gradual  and  irreparable 
wearing  out  of  the  vital  machinery.  Yet  if  we  turn  to 
any  work  on  vital  statistics,  such  as  a  Registration  Report, 
we  find  far  more  prominence  given  to  other  factors  of 
mortality.  In  the  enumeration  of  the  causes  of  death  in 
the  Registration  Report  of  Massachusetts,  for  example, 
there  are  laid  down  five  general  classes  of  causes,  namely, 
as  follows :  — 

I.  Zymotic  Diseases   .         .  (Fevers,  etc.) 

II.  Constitutional  Diseases  .  (Gout,  Cancer,  Scrofula,  Dropsy,  etc.) 

III.  Local  Diseases        .         .  (Apoplexy,  Heart  Disease,  etc.) 

IV.  Developmental  Diseases  (Teething,  Old  Age,  etc.) 

V.     Violence          .         .         .     (Drowning,  Murder,  Accidents,  etc.) 


THE  PRINCIPAL  AGENTS  OF  DEATH       9 

If  we  look  for  old  age,  we  find  it  under  Class  IV  counted  as 
a  disease  along  with  teething,  —  an  equally  normal  process 
of  the  living  organism.  The  great  variety  in  the  causes 
of  death  may  be  still  more  clearly  seen  by  counting  the 
subdivisions  of  the  foregoing  classes  which  are  in  number 
as  follows  in  the  Registration  Report  referred  to :  — 

1 32  Causes  of  Death 

II 10          "       «      " 

III 48          "       "      " 

IV 10          "       «      « 

V 14          "       "      " 

It  will  be  seen  that  Classes  I-IV  include  seven-eighths 
of  all  the  recognized  causes  of  death.  In  other  words, 
various  forms  of  disease  constitute  seven-eighths  of  all  the 
recognized  causes  of  death,  and  it  only  requires  a  some- 
what closer  examination  of  mortality  tables  to  show  that 
old  age  is  assigned  as  the  cause  of  death  in  a  very  small 
percentage  of  cases. 

§  5. — Disease,  not  Old  Age,  the  Principal  Agent  of  Death 

• 

From  the  previous  paragraph  it  is  clear  that  disease  is 
the  cause  of  death  most  often  assigned  by  physicians  in 
filling  out  their  official  certificates;  while  old  age,  which 
may  be  considered  the  most  natural  cause,  is  compara- 
tively rare.  But  this  is  much  more  apparent  than  real, 
since  it  often  happens  that  disease  would  have  been  power- 
less to  cause  death  if  the  vital  machinery  had  not  already 
been  weakened  by  age.  To  what  extent  death  is  really 
due  to  age  it  is,  and  always  must  be,  impossible  to  say. 
The  truth  appears  to  be  that  many  deaths  occur  under, 
and  are  attributed  to,  disease  which  would  not  have  been 
able  to  cause  death  had  the  victim  been  either  older  or 
younger;  while,  on  the  other  hand,  death  would  not  have 
occurred  when  it  did  if  disease  had  been  absent. 

There  occurred  in  Massachusetts,  in  1890,  45,108  deaths 


10  HEALTH,  OLD  AGE  AND  DISEASE 

from  specified  causes,  and  all  but  1814,  or  four  per  cent, 
were  assigned  by  the  physicians  reporting  them  to  the 
effect  of  some  disease.  Disease,  violence  and  old  age, 
then,  would  appear  to  be  the  principal  causes  of  death; 
disease  causing  about  ninety-two  per  cent,  violence  four 
per  cent,  and  old  age  four  per  cent,  and  if  disease  is  thus 
in  reality,  as  it  is  apparently,  the  principal  agent  of  death, 
it  is  obviously  to  the  prevention  of  disease  that  sanitary 
science  must  address  itself.  Hence  has  arisen  its  synonym 
"  preventive  medicine,"  i.e.  such  action  as  shall  prevent  the 
ravages  of  disease. 

§  6.  —  Another  Classification  of  the  Causes  of  Death 

A  simpler,  and  for  our  purpose  more  helpful,  view  of 
the  causes  of  death  is  one  which  seeks  to  classify  them 
roughly  according  to  their  apparent  place  of  origin,  simply 
regarding  them  as  either  — 

(a)  Intrinsic  causes,  or  arising  within  the  body  proper,  or 

(b)  Extrinsic  causes,  arising  outside  the  body  or  acting 
upon  it  from  without. 

From  this  standpoint  diseases  may  be  regarded  as  due 
either  to  defects  in  the  constitution  or  construction  of  the 
vital  mechanism,  or  else  to  external  unfavorable  influences 
acting  upon  it.  From  the  point  of  view  of  origin  or  causa- 
tion, all  diseases  may  be  divided  into  two  classes,  viz. :  - 

I.     Constitutional,  or 
II.     Environmental 

This  classification,  while  open  to  many  objections,  is  of 
the  highest  value  to  the  physiologist  and  the  sanitarian, 
for  it  brings  the  former  face  to  face  with  intrinsic,  struc- 
tural, or  organic  defects  in  the  mechanism,  while  the  atten- 
tion of  the  latter  is  concentrated  upon  those  abnormal 
external  influences  which  act  unfavorably  upon  the  organ- 
ism, and  which  he  must  seek,  and  may  be  able,  to  remove. 


BIOLOGY  AND   SANITATION  II 

A  count  of  the  principal  causes  of  death  laid  down  in  the 
Registration  Report  of  Massachusetts  shows  that  on  this 
basis,  and  approximately  speaking,  there  are  there  given  — 

(1)  Extrinsic  or  environmental  causes  of  death  ....     56 

(2)  Intrinsic  or  constitutional        "      "       "      ....     58 

In  other  words,  one-half  of  the  principal  assigned  causes 
of  death,  from  this  point  of  view,  may  be  said  to  proceed 
from  within  the  organism  and  one-half  from  without ;  one- 
half  would  therefore  lie  within  the  domain  of  the  physiol- 
ogist and  one-half  within  the  field  of  the  sanitarian.  It 
will  be  found  instructive  to  carry  this  line  of  thought 
considerably  further,  as  in  the  next  following  sections, 
carefully  keeping  in  mind  the  fact  that  many  so-called 
intrinsic  causes  probably  have  in  reality,  though  perhaps 
only  remotely,  an  extrinsic  source  or  origin. 

"  Any  arrangement  of  diseases  is  valuable  so  far  as  it 
helps  the  memory  to  retain  useful  facts ;  any  arrangement 
is  useless  or  mischievous  if  it  pretend  to  be  a  universal 
or  '  natural '  or  '  scientific '  system.  Diseases  are  not 
natural  objects ;  they  are  physiological  states,  which  we 
sometimes  define  by  their  cause,  as  plumbism  [lead-poison- 
ing] and  scabies  [itch] ;  sometimes  by  their  histology,  as 
sclerosis  of  the  spinal  cord  and  epithelial  cancer  of  the 
lip ;  sometimes  by  their  constancy  in  transmission,  as 
measles  and  typhus ;  and  sometimes  by  more  or  less  con- 
stant concurrence  of  symptoms,  as  chorea  and  epilepsy."  x 

§  7.  —  Intrinsic  or  Structural  Defects  of  the   Vital 
Machinery ;    Constitutional  Diseases 

The  human  body  is  a  wonderful  machine,  an  admirable 
piece  of  mechanism.  Like  other  complicated  machines, 
it  has  a  definite  structure  and  interdependent  and  recip- 
rocating parts.  These  are  naturally  adjusted  to  the  per- 

1  Pye-Smith,  "  Diseases  of  the  Skin,"  London,  1893. 


12  HEALTH,   OLD   AGE   AND   DISEASE 

formance  of  certain  duties  or  functions,  and  a  failure  of 
one  part  may  involve  the  failure  of  all  other  parts  and 
thus  of  the  entire  vital  apparatus.  If,  for  example,  the 
heart  is  defective  and  fails  to  do  its  duty,  the  circulation 
is  affected  unfavorably  and  the  whole  body  suffers.  It 
needs  no  further  argument  or  illustration  to  show  that  a 
structural  flaw  or  defect  in  the  living  machine  may  mean 
disaster  and  death,  however  favorable  all  external  condi- 
tions may  be.  A  condition  of  the  blood,  or  a  roughness 
upon  the  valves  of  the  heart,  which  shall  produce  a  clot, 
or  a  weakening  of  an  arterial  wall  in  the  brain  which  shall 
finally  produce  cerebral  hemorrhage  or  cause  apoplexy, 
is  an  intrinsic  or  structural  defect  which  may  not  be 
directly  attributable  to  any  unfavorable  external  condi- 
tion. It  may  be  a  flaw  in  the  machine,  an  intrinsic  and 
perhaps  inherited  defect  of  structure ;  and,  if  so,  it  is 
remediable  only  by  fundamental  changes  in  organization 
which  sanitary  science  cannot  hope  to  establish,  unless 
after  many  generations  and  by  steps  which  are  at  present 
quite  beyond  its  reach.  Diseases  of  this  class  are  dis- 
eases of  construction,  i.e.  "  intrinsic  "  or  "  constitutional." 
They  belong  as  yet  in  the  field  of  the  biologist,  the  physi- 
ologist and  the  hygienist  rather  than  that  of  the  sanitarian ; 
to  personal  hygiene,  rather  than  public  hygiene  or  sanitary 
science. 

§  8.  —  Extrinsic  or  External  Interferences  with  the    Vital 
Machinery ;   Environmental  Diseases 

The  human  body  is  subject  —  sensitive,  even  —  to  exter- 
nal conditions :  cold  or  heat,  fire  or  water,  may  so  act  upon 
the  human  body  as  to  produce  death  by  freezing,  burning, 
or  drowning.  Forces,  such  as  gravity  or  electricity,  may 
be  causes  of  death  by  falling,  crushing  or  execution. 
These  and  similar  causes  are  clearly  extrinsic  or  environ- 
mental, and  come  under  the  head  of  accident  or  violence 
—  unless  we  except  suicide  as  perhaps  due  to  constitu- 


CONSTITUTIONAL  VS.  ENVIRONMENTAL  DISEASE       13 

tional  peculiarities.  Some  diseases  have  already  been 
spoken  of  as  constitutional  or  intrinsic,  but  many  dis- 
eases do  not  come  under  this  head.  The  common 
expression  which  describes  an  infectious  disease  as  an 
"attack"  is  noteworthy  as  indicating  the  popular  recog- 
nition of  the  fact  that  disease  often  has  its  source  out- 
side of  the  body.  It  is  now  believed  that  many  diseases 
originate  exclusively  from  unfavorable  environmental  in- 
fluences, and  since  the  celebrated  discovery  of  1839  of 
the  vegetable  nature  of  the  cause  of  favus  (honeycomb 
of  the  scalp),  it  has  been  found  that  not  a  few  diseases 
are  due  to  parasites,  which  invade  the  organism  and  inter- 
fere with  its  normal  working. 

§  9.  —  The  Prevention  of  Constitutional  Diseases  the  Special 
Function  of  Personal  Hygiene 

If  diseases  due  to  defects  or  flaws  in  the  vital  machinery 
are  to  be  avoided,  this  is  obviously  to  be  done  only  by 
improving  and  perfecting  the  apparatus,  which  is  a  com- 
paratively slow  and  difficult  matter.  To  make  a  family 
of  weak  constitution  strong,  is  to  reconstitute  its  entire 
physical  basis ;  and  if  this  can  be  done  at  all,  it  may  be 
only  after  generations  shall  have  come  and  gone.  It  must 
be  done  by  careful  living  and  good  feeding,  wise  inter- 
marriage and  severe  natural  selection.  To  ward  off  adven- 
titious disease  is,  in  these  cases,  not  enough.  The  whole 
structure  must  be  made  over.  Sanitation  alone  cannot 
hope  to  effect  these  changes.  They  must  come  from 
scientific  hygiene  carefully  applied  throughout  long 
generations. 

§  10.  —  Extrinsic  or  Environmental  Diseases  mainly  Pre- 
ventable and  therefore  within  the  Scope  of  Sanitation 

Diseases  which  arise  from  some  invasion  of  the  organism 
may  possibly  be  warded  off.  As  they  virtually  proceed 


14  HEALTH,   OLD   AGE  AND   DISEASE 

from  the  environment  which,  in  theory  at  least,  is  under 
our  control,  they  may  be  prevented.  With  such  diseases 
the  sanitary  science  of  to-day  is  chiefly  concerned.  Sanita- 
tion has  stamped  out  small-pox  in  many  civilized  com- 
munities. It  is  seeking  to-day,  with  more  or  less  success, 
to  do  away  with  typhoid  fever.  It  boldly  attacks  epidemics 
of  diphtheria  and  scarlet  fever,  and  has  recently  sought  to 
control  tuberculosis  and  malaria.  There  can  be  no  ques- 
tion that  it  has  already  won  signal  victories,  and  that  its 
practitioners  may  reasonably  hope  for  fresh  laurels  in  the 
near  future. 

§  ii.  —  The  Prevention  of  Premature  Death  the  Principal 
Function  of  Hygiene  and  Sanitary  Science 

From  what  has  been  said  above  it  would  appear  that  dis- 
ease is  the  principal  agent  of  death.  But  it  must  be  kept  in 
mind  that  disease  (except  in  infants)  is  often  facilitated  in 
its  work  by  age  or  enfeeblement,  which  gives  it  a  foothold 
and  incapacitates  the  organism  for  resisting  its  activity. 
Physiologists  and  physicians  recognize  differences  of  con- 
dition in  which  the  body  seems  to  possess  great  powers 
of  resistance  or  endurance,  or  only  small  powers  (p.  71). 
In  this  way  it  often  happens  that  a  structural  or  constitu- 
tional enfeeblement  exposes  the  organism  to  the  invasion 
of  environmental  disease ;  as,  for  example,  a  low  condition 
of  vitality  is  generally  believed  to  increase  enormously  the 
susceptibility  to  attacks  of  typhoid  fever ;  and  as  soldiers, 
enfeebled  by  long  marches  or  bad  feeding,  appear  to  suffer 
unduly  from  certain  camp  diseases. 

A  little  reflection  will  show  that  death,  as  a  rule,  comes 
prematurely.  Old  age,  the  only  theoretically  normal  and 
natural  cause  of  death,  is  very  rarely  the  one  and  only 
cause.  Poor  timber  or  poor  materials  or  poor  construction 
of  the  living  machinery,  alone  or  together  making  up  a 
poor  "constitution,"  or  else  violence,  poison,  parasites  or 


THE  FUNCTIONS   OF  HYGIENE  15 

other  unfavorable  elements  in  the  environment,  usually 
bring  on  disease  and  death  long  before  the  appointed 
threescore  years  and  ten,  or  the  rarer  fourscore  years. 
Many  die  before  they  are  born ;  more  before  one  year  of 
life  is  over ;  others  under  five  years,  ten  or  twenty.  A 
few  live  on  for  thirty,  forty  or  fifty  years;  but  for  the 
great  majority  death  comes  before  old  age,  before  "the 
lean  and  slipper'd  pantaloon."  All  this  means  that  death 
is  oftenest  premature ;  and  the  principal  function  of  sani- 
tation and  of  the  applications  of  hygiene  in  general  is  the 
prevention  of  premature  death.  Hygiene  in  its  widest 
sense  goes  further,  and  seeks  to  elevate  or  maintain  at  a 
high  level  the  standard  of  normal  living. 

§  12.  —  Hygiene  and  Sanitary  Science 

Sanitary  science  is  the  science  of  health.  It  is  com- 
monly held  to  be,  and  commonly  it  is,  much  the  same 
thing  as  hygiene.  Sciences  and  arts,  however,  like  living 
organisms,  grow,  differentiate  and  divide,  and  hygiene  is 
no  exception  to  the  rule.  The  wonderful  developments 
which  have  taken  place  within  the  last  half  century  in  our 
knowledge  of  the  causes  of  disease,  and  especially  those 
diseases  proceeding  from  the  environment,  together  with 
the  corresponding  advancement  in  our  arts  for  their  pre- 
vention or  control, — the  sanitary  arts, — have  brought  about 
a  differentiation  of  hygiene  such  that  one  portion  of  it  now 
deals  naturally  and  mainly  with  the  environment  of  man, 
while  another  portion  deals  naturally  and  mainly  with  man 
himself. 

As  the  environment  is  usually  shared  in  common  by 
many  persons,  that  branch  of  hygiene  which  deals  mainly 
with  the  environment  may  conveniently  be  called  "  public  " 
hygiene;  while  the  remainder,  dealing  as  it  does  chiefly 
with  the  individual,  may  properly  be  designated  "personal  " 
hygiene.  Underlying  both  personal  and  public  hygiene 


1 6  HEALTH,   OLD   AGE   AND   DISEASE 

there  are  certain  fundamental  principles  of  the  causation 
and  prevention  of  disease  which  are  absolutely  essential 
to  all  sound  practice  of  the  sanitary  arts.  These,  steadily 
growing  in  number  and  importance  as  the  years  go  by, 
constitute  the  firm  foundation  on  which  both  the  theory 
and  the  practice  of  personal  and  public  hygiene  rest. 
Moreover,  because  they  are  founded  largely  upon  experi- 
ment, and  are  in  harmony  with  established  laws  of  nature, 
they  may  be  said  to  constitute  the  beginnings,  at  least,  of 
a  sanitary  "science."  Furthermore,  inasmuch  as  the  en- 
vironment is  not  only  more  accessible  for  treatment  than 
the  individual,  but  also  far  more  under  our  influence  and 
control,  it  has  naturally  come  to  pass  that  sanitary  science 
consists  very  largely  of  principles  derived  from,  and  ap- 
plicable to,  problems  relating  to  the  environment  rather 
than  the  individual.  Hence  it  happens  that  it  is  at  pres- 
ent most  often  and  most  naturally  associated  with  public 
hygiene  or  the  public  health  rather  than  with  general 
hygiene  or  with  personal  hygiene,  or  the  health  of  the 
individual. 

The  whole  subject  of  proper  food  and  clothing,  for 
example,  pertains  to  general  or  personal  hygiene ;  but 
sanitary  science  is  more  especially  concerned  with  infected 
food  and  clothing.  Whether  the  citizens  of  Boston  or 
Paris  dress  warmly  enough,  or  too  warmly ;  whether  cot- 
ton, linen  or  wool  is,  on  the  whole,  the  most  suitable  for 
the  climate  of  New  York  or  London  at  all  seasons  or  at 
any  season  —  these  are  questions  of  general  or  of  per- 
sonal hygiene ;  but  the  question  of  infection  by  means  of 
clothing  made  in  the  den  of  the  sweater;  the  question 
of  the  disinfection  of  Egyptian  rags  arriving  in  the  harbor 
of  London  or  Boston ;  the  conveyance  of  disease  germs 
by  the  clothing  of  persons  dead  of  small-pox  or  scarlet 
fever  —  these  are  the  peculiar  property  of  sanitary  science 
and  the  public  health.  To  sanitary  science  and  the  public 
health  belong  also  questions  of  polluted  water,  polluted 


SANITARY   SCIENCE   OR  HYGIOLOGY  17 

milk  and  polluted  air;  questions  concerning  the  origin, 
dangers  and  disposal  of  sewage ;  questions  relating  to 
dust  and  disease  and  to  the  natural  history  of  epidemics. 
The  practice  of  sanitary  science  is  founded,  as  applied 
science  must  always  be  founded,  upon  a  basis  of  estab- 
lished truth.  Upon  this  sure  basis  we  may  construct  a 
framework  of  philosophical  explanation,  or  theory,  by  the 
aid  of  which  we  may  hope  to  make  or  measure  new  dis- 
coveries. Though  often  unrecognized,  some  such  working 
theory  lies  at  the  bottom  of  all  sanitary  endeavor.  It  has 
underlain  the  prayers  and  incantations  of  savages ;  it  under- 
lies all  quarantine  regulations ;  it  is  at  the  foundation  of  all 
sanitary  authority. 

The  past  fifty  years  have  witnessed  vast  additions  to 
our  store  of  established  truth,  and  vast  changes  in  our 
stock  of  theory,  underlying  all  the  application  of  sanitary 
science.  These  additions  we  owe  almost  wholly  to  one 
simple  mechanical  discovery  in  the  domain  of  physics  — 
the  discovery  how  to  make  an  achromatic  microscope 
objective.  This  discovery  so  facilitated  and  stimulated 
the  use  of  the  microscope  that  it  has  revolutionized  ideas 
of  the  causation  of  disease;  has  established  physiology 
upon  a  broad  and  firm  foundation ;  and  has  created  new 
sciences  of  immense  importance,  such  as  general  biology, 
pathology  and  bacteriology. 

§  13. — Definitions 

As  a  recapitulation  of  the  foregoing  paragraphs  the 
following  definitions  may  be  found  useful  for  beginners, 
although  like  most  definitions  they  are  only  approximately 
correct  and  must  not  be  taken  too  literally. 

HYGIENE 

Hygiene  {general  hygiene)  is  the  whole  science  and  art 
of  the  conservation  and  promotion  of  health  both  in  indi- 


1 8  HEALTH,  OLD  AGE  AND  DISEASE 

viduals  and  in  communities.  It  has  for  its  function  the 
prevention  of  premature  death  and  the  promotion  of  nor- 
mal life,  health  and  happiness  both  directly  by  conservation 
and  reinforcement  of  organisms  and  groups  of  organisms ; 
and  indirectly  by  the  elimination  or  amelioration  of  unfa- 
vorable environmental  conditions  both  local  and  general. 

The  field  of  hygiene  is  immense,  for  it  includes  not  only 
all  of  sanitary  science  and  the  sanitary  arts,  but  a  large  part 
of  physiology  and  even  of  biology  as  well.  It  includes  not 
only  questions  of  water  supply,  milk  supply  and  sewerage, 
but  also  much  of  climatology,  foods  and  feeding,  clothing, 
heating,  lighting,  ventilation,  vaccination,  scavenging,  the 
personal  care  of  the  body,  work  and  overwork,  sleep,  rest, 
fatigue,  exercise,  play,  sports,  noise,  crowding  and  over- 
crowding, and  other  subjects  too  numerous  to  mention  but 
comprised  in  part  under  the  heads  of  public  hygiene  and 
personal  hygiene,  municipal  sanitation,  school  sanitation, 
household  sanitation,  offensive  trades,  unwholesome  or 
dangerous  trades,  quarantine,  toxicology,  etc. 

PUBLIC    HYGIENE 

Public  hygiene  is  the  science  and  the  art  of  the  conserva- 
tion and  promotion  of  the  public  health.  It  has  for  its 
function  the  prevention  of  premature  death  and  the  promo- 
tion of  normal  life,  health  and  happiness  in  communities 
chiefly  by  the  elimination  or  amelioration  of  unfavorable 
environmental  conditions  common  to  many  persons  or  com- 
munities either  at  one  time  or  at  different  times. 

It  includes  especially  hygienic  problems  common  to 
groups  or  communities,  such  as  camps,  villages,  towns 
and  cities,  e.g.  water  supplies,  drainage,  milk  supplies,  ice 
supplies,  the  control  of  infectious  diseases,  heating,  light- 
ing, ventilation,  school  sanitation,  municipal  sanitation, 
and  the  like.  The  establishment  of  municipal  gymnasia 
in  many  cities  shows  that  the  necessity  of  muscular  exer- 
cise under  the  conditions  of  urban  life  is  becoming  a  ques- 


DEFINITIONS  19 

tion  of  public  as  it  has  long  been  of  personal  hygiene. 
There  is  undoubtedly  a  natural  tendency  for  all  questions 
of  personal  hygiene  to  become  more  and  more  problems  of 
public  hygiene. 

PERSONAL   HYGIENE 

Personal  hygiene  is  the  science  and  art  of  the  conservation 
and  promotion  of  personal  health,  and  has  for  its  function 
the  prevention  of  premature  death  and  the  promotion  of  nor- 
mal individual  life,  health  and  happiness  cliiefly  by  direct 
conservation  and  reenforcement  of  that  physical  mechanism 
which  we  call  the  human  body. 

It  includes  especially  problems  relating  to  proper  foods 
and  feeding  of  the  individual,  his  sleep  and  rest,  his  work 
and  fatigue,  his  muscular  exercise,  stimulants  and  narcotics, 
the  care  of  the  eyes,  the  ears,  the  teeth,  the  bowels,  the 
hair  and  other  organs,  clothing  for  special  conditions,  etc. 

SANITARY    SCIENCE  (HYGIOLOGY) 

Sanitary  science  (Jtygiology)  is  that  body  of  hygienic  or 
sanitary  knowledge  which  having  been  sufficiently  and  criti- 
cally examined  has  been  found  so  far  as  tested  to  be  invari- 
ably true.  •  Its  phenomena  are  natural  phenomena,  its  laws 
are  natural  laws,  its  principles  are  scientific  principles. 

It  includes  those  hygienic  facts  and  theories  which  have 
been  so  thoroughly  verified  by  repeated  observation  and 
experiment  as  to  have  become  worthy  to  rank  as  scientific 
principles.  A  good  example  of  such  a  body  of  fact  and 
theory  is  that  which  underlies,  and  is  correlated  by,  the 
germ  theory  of  infectious  disease,  which  is  described  in 
the  next  chapter.  Like  some  other  sciences,  while  largely 
inductive  it  is  also  in  part  deductive. 

THE   SANITARY   ARTS 

The  sanitary  arts  are  those  methods  and  processes  by 
which  the  applications  of  the  principles  of  sanitary  science  or 
hygiene  are  effected. 


20  HEALTH,   OLD   AGE   AND   DISEASE 

They  include  the  practical  processes  involved  in  all 
sanitary  engineering  and  architecture,  e.g.  in  water-supply, 
sewerage,  ventilation  and  heating,  municipal  sanitation, 
school  hygiene,  etc.  Among  the  most  important  are 
the  construction  and  operation  of  reservoirs,  niters,  con- 
duits, sewers,  sewage  fields  and  hygienic  schoolhouses, 
the  cultivation  and  preparation  of  vaccine,  the  manufac- 
ture of  antitoxines,  the  inspection  of  foods  and  drugs,  the 
examination  of  drinking  waters,  the  disposal  of  garbage 
and  refuse,  the  construction  and  maintenance  of  streets, 
the  abatement  of  nuisances,  the  control  of  dangerous  or 
offensive  trades,  etc. 


CHAPTER   II 

ON  AETIOLOGY  OR  THE  CAUSES  OF  DISEASE.  ANCIENT  AND 
MODERN  THEORIES.  THE  ZYMOTIC  (FERMENT)  OR  GERM 
THEORY  OF  INFECTIOUS  DISEASE 

'( How  far  the  power  of  spirits  and  devils  doth  extend  and  whether 
they  can  cause  this  or  any  other  disease,  is  a  serious  question  and 
worthy  to  be  considered.'1  —  BURTON'S  "Anatomy  of  Melancholy." 

"  Diseases  and  death  are  the  consequences  and  effects  of  sin ;  this  is 
the  idea  which  we  have  of  them  from  Scripture." 

—  CRUDEN'S  "  Concordance." 

"  Diseases  have  been  generally  considered  as  the  inevitable  inflic- 
tions of  Providence."  —  MALTHUS. 

"  Diseases  .  .  .  will  perhaps  be  never  properly  understood  without 
an  insight  into  the  doctrine  of  fermentations."  —  BOYLE. 

"  Side  by  side  with  these  .  .  .  has  run  the  germ  theory  of  epidemic 
disease.  The  notion  was  expressed  by  Kircher,  and  favored  by  Lin- 
naeus, that  epidemic  diseases  may  be  due  to  germs  which  .  .  .  enter  the 
body,  and  produce  disturbance  by  the  development  within  the  body  of 
parasitic  life."  — TYNDALL. 

u  Moreover,  if  inquiry  into  the  origin  and  conditions  of  disease  helps 
treatment,  it  is  indispensable  for  the  still  better  art  of  prevention.  That 
depends  entirely  upon  the  extent  of  our  knowledge  of  aetiology." 

—  PYE-SMITH. 

THE  sanitarian  must  have  sound  working  theories  of 
disease.  If  he  is  to  maintain  and  promote  the  public 
health,  he  must  be  familiar  with  the  causes  of  disease 
and  the  avenues  along  which  they  travel.  In  order  to 
prevent  disease  he  must  know,  if  possible,  precisely  what 
disease  is.  To-day  all  civilized  and  scientific  persons  re- 
gard disease,  as  has  been  indicated  in  the  preceding 
chapter,  as  a  state  or  condition  of  disturbance  or  abnor- 


22  /ETIOLOGY   OR   THE   CAUSES   OF   DISEASE 

mality1  which  the  body  has  unfortunately  assumed  or 
been  placed  in.  Savage  and  uncivilized  people,  on  the 
contrary,  and  the  unscientific  civilized,  are  apt  to  look  upon 
disease  as  an  entity,  something  to  be  pacified,  cajoled  or 
cast  out.  Very  often  this  entity  is  personified,  and  illus- 
trates that  subjective  characteristic  which  is  so  marked  a 
feature  of  primitive  culture. 

§  i. —  The  Demonic  Theory  of  Disease* 

The  earliest  theories  of  disease  with  which  we  are  ac- 
quainted are  found  among  savage  races,  which  naturally 
interpret  fever,  sickness,  pain,  madness  and  hysteria  as 
due  to  the  temporary  or  prolonged  occupancy  of  the 
affected  body  by  an  evil  spirit  or  demon.  This  is  called 
the  Demonic  Theory.  The  same  subjective,  anthropomor- 
phic method  of  thought  which  sees  in  the  sun,  not  a  huge 
sphere  of  burning  matter  giving  light  and  life  to  other 
worlds,  but  Apollo,  a  god,  driving  his  chariot  of  fire  daily 
across  the  sky ;  or  fills  the  woods  with  fauns  and  satyrs, 
and  the  streams  with  nymphs  and  naiads,  naturally  looks 
for  the  causes  of  disease  in  human  or  inhuman  forms  dis- 
torted and  misshapen  according  to  the  fancy,  but  gifted 
with  human  cunning  and  more  than  human  malignity.3 

1  "  Disease  is  a  state  of  a  living  organism  .  .  .  the  disease  itself  is  a  per- 
turbation. .  .  ."  —  ALLBUTT,  "Syst.  Med.,"  I.  xxiv. 

2  For  the  substance,  and  to  a  great  extent  the  form,  of  this  entire  section 
the   author   is   indebted   to  various  writings  of  that   eminent   authority   on 
primitive  culture,  Professor  E.  B.  Tylor. 

8  "  Among  races  of  low  culture,  the  conception  of  a  ghost  soul  being  made 
to  account  for  the  phenomena  of  life  readily  leads  to  a  corresponding  theory 
of  morbid  states  of  body  and  mind.  As  the  man's  proper  soul  causes  the 
functions  of  normal  life  by  its  presence,  while  its  more  or  less  continued 
absence  induces  sleep,  trance,  and  at  last  death,  so  the  abnormal  phenomena 
of  disease  have  a  sufficient  explanation  at  hand,  in  the  idea  that  some  other 
soul  or  soul-like  spirit  is  acting  on  or  has  entered  the  patient.  Among  the 
cases  which  most  strongly  suggest  this,  are :  first,  such  derangements  as  hys- 
teria, epilepsy,  and  madness,  where  the  raving  and  convulsions  seem  to 


PRIMITIVE   THEORIES   OF  DISEASE  23 

The  demonic  theory  regards  disease  as  a  supernatural 
being  or  entity,  not  primarily  as  a  process  or  condition, 

by-standers  like  the  acts  of  some  other  being  in  possession  of  the  patient's 
body,  and  even  the  patient  is  apt  to  think  so  when  he  '  comes  to  himself; 
and  second,  internal  diseases  where  severe  pain  or  wasting  away  may  be 
ascribed  to  some  unseen  being  wounding  or  gnawing  within.  This  applicabil- 
ity of  demoniacal  possession  as  a  theory  to  explain  disease  in  general  is  best 
proved  by  the  fact  that  it  is  so  often  thus  applied  by  savage  races.  Especially, 
reasoning  out  the  matter  in  similar  ways,  rude  tribes  in  different  countries 
have  repeatedly  arrived  at  the  conclusion  that  diseases  are  caused  by  the 
surviving  souls  or  ghosts  of  the  dead  who  appear  to  the  living  in  dreams  and 
visions,  thus  proving  at  once  their  existence  after  death  and  their  continued 
concern  with  mankind.  This  notion  being  once  set  on  foot  it  becomes  easy 
to  the  savage  mind  to  identify  the  particular  spirit,  as  when  the  Tasmanian 
ascribes  a  gnawing  disease  to  his  having  unwittingly  pronounced  the  name  of 
a  dead  man,  who,  thus  summoned,  has  crept  into  his  body  and  is  consuming 
his  liver  ;  or  when  the  sick  Zulu  believes  that  some  dead  ancestor  he  sees  in 
a  dream  has  caused  his  ailment,  wanting  to  be  propitiated  with  a  sacrifice  of 
an  ox  ;  or  when  the  Samoan  persuades  himself  that  the  ancestral  souls,  who 
on  occasion  reveal  themselves  by  talking  through  the  voices  of  living  members 
of  the  family,  are  the  same  beings  who  will  take  up  their  abode  in  the  heads 
or  stomachs  of  living  men  and  cause  their  illness  and  death.  ...  In  many, 
perhaps  in  most,  cases,  however,  the  disease  demon  is  not  specially  described 
as  a  human  ghost ;  for  instance,  some  Malay  tribes  in  their  simple  theory  of 
diseases  are  content  to  say  that  one  kind  of  demon  causes  small-pox,  another 
brings  on  swellings,  and  so  on.  .  .  .  The  savage  theory  of  demoniacal  pos- 
session has  for  its  natural  result  the  practice  of  exorcism  or  banishment  of  the 
spirit  as  the  regular  means  of  cure,  as  where,  to  select  these  from  hundreds  of 
instances,  the  Antilles  Indians  in  Columbus's  time  went  through  the  pretence 
of  pulling  the  disease  off  the  patient  and  blowing  it  away,  bidding  it  begone 
to  the  mountain  or  the  sea;  or  where  the  Patagonians,  till  lately,  believing 
every  sick  person  to  be  possessed  by  an  evil  demon,  drove  it  away  by  beating 
at  the  bed's  head  a  drum  painted  with  figures  of  devils. 

"  That  such  modern  savage  notions  fairly  represent  the  doctrines  of  disease- 
possession  in  the  ancient  world  is  proved  by  the  records  of  the  earliest  civilized 
nations.  The  very  charms  still  exist  by  which  the  ancient  Egyptians  resisted 
the  attacks  of  the  wicked  souls,  who,  become  demons,  entered  the  bodies  of 
men  to  torment  them  with  diseases  and  drive  them  to  furious  madness.  The 
doctrine  of  disease  among  the  ancient  Babylonians  was  that  the  swarming 
spirits  of  the  air  entered  man's  body,  and  it  was  the  exorcist's  duty  to  expel 
by  incantations  '  the  noxious  neck-spirit,'  '  the  burning  spirit  of  the  entrails 
which  devours  the  man,"  and  to  make  the  piercing  pains  in  the  head  to  fly 
away  'like  grasshoppers'  into  the  sky.  .  .  .  No  record  shows  the  ancient 
theory  more  clearly  than  the  New  Testament  from  the  explicit  way  in  which  the 


24          .ETIOLOGY  OR  THE  CAUSES  OF  DISEASE 

and  the  diseased  condition  is  the  result  of  the  influence 
of  some  entity  foreign  to  the  patient,  to  something  acting 

symptoms  of  the  various  affections  are  described,  culminating  in  the  patient 
declaring  the  name  of  his  possessing  demon,  and  answering  in  his  person  when 
addressed.  The  similarity  of  the  symptoms  with  those  which  in  barbarous 
countries  are  still  accounted  for  in  the  ancient  way  may  be  seen  from  such 
statements  as  the  following,  by  a  well-known  missionary  (Rev.  J.  L.  Wilson, 
1  Western  Africa,'  page  207)  :  '  Demoniacal  possessions  are  common,  and 
the  feats  performed  by  those  who  are  supposed  to  be  under  such  influence  are 
certainly  not  unlike  those  described  in  the  New  Testament.  Frantic  gestures, 
convulsions,  foaming  at  the  mouth,  feats  of  supernatural  strength,  furious  rav- 
ings, bodily  lacerations,  gnashing  of  teeth,  and  other  things  of  a  similar  char- 
acter may  be  witnessed  in  both  of  the  cases.'  Among  the  early  Christians 
the  demoniacs  or  energumens  formed  a  special  class  under  the  control  of  a 
clerical  order  of  exorcists,  and  a  mass  of  evidence  drawn  from  such  writers  as 
Cyril,  Tertullian,  Chrysostom,  and  Minutius  Felix  shows  that  the  symptoms 
of  those  possessed  were  such  as  modern  physicians  would  class  under  hysteria, 
epilepsy,  lunacy,  etc.  .  .  .  Some  theologians,  while  in  deference  to  advanced 
medical  knowledge  they  abandon  the  primitive  theory  of  demons  causing 
such  diseases  in  our  own  time,  place  themselves  in  an  embarrassing  position  by 
maintaining,  on  the  supposed  sanction  of  Scripture,  that  the  same  symptoms 
were  really  caused  by  demoniacal  possession  in  the  first  century.  .  .  .  For 
our  times  this  seems  too  like  a  discussion  whether  the  earth  was  really  flat  in 
the  ages  when  it  was  believed  so,  but  became  round  since  astronomers  pro- 
vided a  different  explanation  of  the  same  phenomena.  It  is  more  profitable  to 
notice  how  gradual  the  change  of  opinion  has  been  from  the  doctrine  of 
demon-possession  to  the  scientific  theory  of  disease,  and  how  largely  the 
older  view  still  survives  in  the  world.  Not  only  in  savage  districts,  but  in 
countries  whose  native  civilization  is  below  the  European  level,  such  as  India 
and  China,  the  curious  observer  may  still  see  the  exorcist  expel  the  malignant 
ghost  or  demon  from  the  patient  afflicted  with  fever,  dizziness,  frenzy,  or  any 
accountable  ailment.  .  .  .  The  unbroken  continuance  of  the  belief  in  medi- 
aeval Europe  may  be  gathered  from  various  works.  .  .  .  Even  in  the  eigh- 
teenth century  was  published  with  ecclesiastical  approval  a  regular  exorcist's 
manual,  the  '  Fustis  et  Flagellum  Doemonum,'  Auctore  R.  P.  F.  Hieronimo 
Mengo  (1727),  which  among  its  curious  contents  gives  instructions  how  to 
get  the  better  of  those  cunning  demons  who  hide  in  the  bodies  of  men  and 
vex  them  with  diseases,  and  which  are  apt,  when  expelled,  to  take  refuge  in 
the  patient's  hair.  The  gradual  shifting  of  opinion  is  marked  by  the  attempt 
to  reconcile  the  older  demonology  with  the  newer  medicine.  The  argument, 
which  appears  among  the  early  Christian  fathers,  is  worked  out  most  elabo- 
rately in  that  curious  museum  of  demonology,  the  '  Disquisitiones  Magioe ' 
of  Martin  Delrio,  published  as  late  as  1720.  While  inveighing  against  those 
physicians  who  maintain  that  all  diseases  have  natural  causes,  this  learned  Jesuit 


DISEASES   AND   DEMONIACAL  POSSESSION          25 

from  or  coming  from  the  environment.  Of  any  disease  aris- 
ing from  within,  or  due  to  any  intrinsic  or  mechanical  defect 
or  derangement  of  an  apparatus  —  such  as  faulty  materials 
or  construction  —  the  savage  has  no  conception.  This 
idea  requires  anatomical  information  and  the  power  to 
reflect  from  the  merely  objective  point  of  view;  in  other 
words,  the  modern  mechanical  and  scientific  attitude  of 
mind,  the  objective  rather  than  the  subjective  capacity. 
Even  here,  however,  the  cure  was  logically  applied.  Sav- 
age therapeutics  accurately  followed  savage  pathology.  If 
the  disease  were  due  to  the  possession  of  the  patient  by 
a  demon  or  demons,  nothing  could  be  more  logical  or 
better  medical  practice  than  to  seek  somehow  to  cast  them 
out.  Exhortations,  drums,  or  anything  likely  to  influence 
the  demon  constituted  a  proper  materia  medica.  Most 

admits  that  men  may  be  dumb,  epileptic,  or  lunatic  without  being  obsessed;  but 
what  the  demons  do  is  that,  finding  the  dispositions  of  epileptics  suitable,  they 
insinuate  themselves  into  them;  also  they  attack  lunatics,  especially  at  full  moon, 
when  their  brains  are  full  of  humors,  or  they  introduce  diseases  by  stirring 
up  the  black  bile,  sending  blacks  into  the  brain  and  cells  of  the  nerves,  and 
setting  obstructions  in  the  ears  and  eyes  to  cause  deafness  and  blindness. 
Looking  at  the  date  of  this  celebrated  work,  we  cannot  wonder  that  in 
benighted  districts  of  Europe  the  old  diabolical  possession  and  its  accompany- 
ing exorcism  may  still  now  and  then  be  met  with,  as  in  1861  at  Morzine  in 
Savoy.  The  London  Times,  in  November,  1876,  contained  an  account  of  the 
casting  out  of  devils  by  a  priest  in  the  Church  of  the  Holy  Spirit  in  Barcelona, 
during  the  preceding  month.  On  one  occasion,  the  patient,  a  young  woman 
of  seventeen  or  eighteen,  lay  on  the  floor  before  the  altar,  writhing  in  convul- 
sions, with  distorted  features  and  foaming  at  the  mouth,  while  the  priest 
carried  on  a  dialogue  with  the  devil,  whom  he  addressed  by  the  name  of 
Rusbel,  the  fiend's  answers  being  of  course  spoken  by  the  voice  of  the  frantic 
girl  herself.  At  last  a  number  of  demons  were  supposed  to  come  out  of  the 
patient's  body,  and  such  scenes  were  repeated  for  days  in  the  presence  of 
many  spectators  till  a  riot  arose,  and  the  civil  authorities,  intervening,  put  a 
stop  to  the  whole  affair.  One  of  the  last  notable  cases  of  this  kind  in  England 
was  that  of  George  Lukins  of  Yatton,  a  knavish  epileptic,  out  of  whom  seven 
devils  were  exorcised  by  seven  clergymen,  at  the  Temple  Church  at  Bristol,  on 
June  13,  1788.'— TYLOR. 

..."  Thy  demon,  that's  thy  spirit  that  keeps  thee." 

—  "  Antony  and  Cleopatra." 


26          ETIOLOGY  OR  THE  CAUSES  OF  DISEASE 

effective  of  all  would  be  the  voice  of  a  master  who  should 
command  their  obedience  and  compel  them  to  come  out. 

It  was  even  possible  upon  the  demonic  theory,  crude 
and  childish  as  it  was,  to  have  a  legitimate  "preventive 
medicine."  "The  very  charms  still  exist  by  which  the 
ancient  Egyptians  resisted  the  attacks  of  the  wicked  souls, 
who,  become  demons,  entered  the  bodies  of  men  to  tor- 
ment them  with  disease  and  drive  them  to  furious  mad- 
ness." And  we  all  know  of  survivals  even  to-day  in  the 
charms  and  amulets  which  are  supposed  to  resist  bad 
luck,  and  the  more  material  horseshoe,  rabbit's  foot,  horse- 
chestnut  in  the  trousers  pocket,  etc.,  which  shall  ward  off 
witches  or  disease  from  us  or  from  our  habitations. 

§  2.  —  The  Theory  of  the  Four  Humors 

Long  before  the  period  of  the  highest  development  of 
Greek  civilization,  the  primitive  or  demonic  theory  of  dis- 
ease had  ceased  to  satisfy  the  minds  of  cultivated  men. 
Many  traces  of  it  indeed  remain  in  the  Homeric  time; 
but  with  the  arrival  of  the  age  of  Pericles  we  have  as  his 
contemporary  Hippocrates,  already  called  "the  Great," 
and  ever  since  known  as  the  "  Father  of  Medicine."  And 
now,  apparently,  for  the  first  time,  we  find  "  a  clear  recog- 
nition of  disease  as  being  equally  with  life  a  process  gov- 
erned by  what  we  should  now  call  natural  laws.  .  .  .  The 
actual  science  of  the  Hippocratic  school  was  of  course  very 
limited.  In  anatomy  and  physiology  little  advance  has 
been  made,  and  so  of  pathology  in  the  sense  of  an  expla- 
nation of  morbid  processes  or  knowledge  of  diseased  struc- 
tures there  could  be  very  little.  .  .  .  The  dominating 
theory  of  disease  was  the  humoral,  which  has  never 
since  ceased  to  influence  medical  thought  and  practice. 
According  to  this  celebrated  theory,  the  body  contains 
four  humors,  —  blood,  phlegm,  yellow  bile,  and  black  bile, 
—  a  right  proportion  and  mixture  of  which  constitute 


ANCIENT   AND   MEDIEVAL  THEORIES  27 

health;  improper  proportion  and  irregular  distribution, 
disease.  It  is  doubtful  whether  the  treatise  in  which  this 
theory  is  fully  expounded  is  as  old  as  Hippocrates  him- 
self ;  but  it  was  regarded  as  a  Hippocratic  doctrine,  and 
when  taken  up  and  expanded  by  Galen,  its  terms  not  only 
became  the  common  property  of  the  profession,  but  passed 
into  general  literature  and  common  language.  Another 
Hippocratic  doctrine,  the  influence  of  which  is  fortunately 
not  even  yet  exhausted,  is  that  of  the  healing  power  of 
nature."  1  Much  of  the  language  of  this  famous  theory 
still  lingers,  as  when  we  speak  of  a  "bilious"  condition, 
a  "sanguine,"  "phlegmatic,"  or  "melancholic"  (black 
bile)  temperament.  It  had  the  high  merit  under  Hippo- 
crates of  fixing  attention  upon  natural  rather  than  super- 
natural causes,  upon  the  patient  rather  than  demons.2 

§  3.  — Roman,  Arabian  and  Mediceval  Theories  of  Disease 

We  need  not  follow  in  detail  the  shifting  opinions  of 
mankind  as  to  the  true  causes  of  disease  between  the  time 
of  Hippocrates  (500  B.C.)  and  that  of  Sydenham.  In  the 
decline  of  Greek  culture  and  the  Alexandrian  period  no 
new  ideas  of  importance  were  successfully  advanced  or 
long  maintained.  The  theory  of  the  four  humors,  with 
various  modifications  and  under  various  forms,  prevailed, 
and  even  in  the  hands  of  Galen  during  the  Roman  period, 
though  expanded  and  highly  elaborated  so  that  it  became 
the  standard  authority  for  many  centuries,  remained  essen- 
tially the  same.  During  the  Dark  Ages  no  important  new 

1  J.  F.  Payne ,  M.D.,  on  the  "  History  of  Medicine,"  Encyclopedia  Bri- 
tannica,  gth  ed.,  Vol.  XVII,  p.  800. 

2  "  The  four  Galenical  humors,  viz.,  the  blood  which  took  its  origin  in  the 
liver,  the  phlegm  secreted  by  the  pituitary  gland,  the  bile  by  the  gall,  and  the 
black  bile  by  the  spleen.      From  the  mixture  of  these  humors  arose  the  four 
natural  'temperaments':    sanguine,  in   which  the  blood  was  predominant; 
phlegmatic  or  pituitous;   bilious  or  choleric;   atrabilious  or  melancholic;   and 
from  the  ill-mixture  of  these  ingredients  resulted  dyscrasia  and  new  morbid 
humors,  such  as  produced  scurvy,  scrofula  and  gout."  —  PYE-SMITH. 


28  ETIOLOGY   OR  THE   CAUSES   OF   DISEASE 

ideas  were  introduced  into  Europe  by  the  Arabian  physi- 
cians, Avicenna  and  Rhazes;  for  these  authors  worked 
largely  upon  the  foundations  laid  by  Hippocrates  and 
Galen,  and  their  theories  need  not  detain  us.  The  period 
of  scholasticism  also  yielded  nothing  in  the  theory  of 
disease  beyond  the  four  humors,  but  only  endless  com- 
mentaries on  Hippocrates  and  Galen  similar  in  character 
to  those  in  philosophy  upon  Aristotle.  Even  for  some 
time  after  the  revival  of  learning  and  the  splendid  period 
of  the  Renaissance,  this  very  revival  being  in  the  hands 
of  "medical  humanists"  led  to  a  renewed  respect  for 
ancient  authority,  and  more  than  ever  Hippocrates  and 
Galen  were  regarded  as  authorities  while  the  theory  of  the 
four  humors  naturally  held  full  sway.  With  Paracelsus 
(1480-1541),  however,  emphatic  doubts  began  to  be  boldly 
expressed  as  to  the  sufficiency  of  the  ancient  theories. 
The  study  of  anatomy  in  Italy  in  the  sixteenth  century 
under  Vesalius,  Fallopius,  Fabricus  and  many  others, 
followed  as  it  was  early  in  the  seventeenth  by  Harvey's 
marvellous  discovery  of  the  circulation  of  the  blood,  to- 
gether with  the  general  progress  of  knowledge,  finally 
raised  grave  doubts  in  the  best  minds  as  to  the  true  causes 
of  disease,  doubts  which  were  powerfully  supported  by  the 
occurrence  in  Europe  in  the  fifteenth  and  sixteenth  centu- 
ries of  certain  highly  destructive  epidemic  diseases,  some 
of  them  hitherto  unknown  and  all  quite  inexplicable  on 
the  theory  of  the  four  humors.  Meantime  there  arose 
two  schools,  called  respectively  the  "  iatro-physical "  and 
"iatro-chemical,"  the  former  basing  itself  on  physiology 
and  mechanical  explanations  of  disease,  the  latter  on  chem- 
ical or  fermentative  processes.  "  The  intestine  movement 
of  particles,"  or  "fermentation,"  was  the  essence  of  the 
latter,  the  application  of  physics  and  mechanics  to  the 
body  that  of  the  former.  The  name  of  Sylvius  (1614- 
1672)  is  widely  known  in  connection  with  the  iatro-chem- 
ical school.  These  schools,  however,  were  compelled  to 


THEORIES   OF   THE   RENAISSANCE  29 

struggle  not  only  each  with  the  other  but  both  with  the 
ancient  (Hippocratic)  doctrines. 

§  4.  —  The  Theory  of  Sydenham 

Thomas  Sydenham  (1644-1689),  who  has  been  called 
"the  English  Hippocrates,"  held  as  "his  main  avowed 
principle  to  do  without  hypothesis  and  study  the  actual 
diseases  in  an  unbiassed  manner."  According  to  Syden- 
ham, "  a  disease  is  nothing  more  than  an  effort  of  nature 
to  restore  the  health  of  the  patient  by  the  elimination  of 
the  morbific  matter."  This  full  recognition  of  a  materies 
morbi  was  a  distinct  advance,  and  foreshadows  the  time 
when  the  materies  morbi  would  itself  be  regarded  as 
specific  in  specific  diseases.  Sydenham  appears  to  have 
recognized  the  fact  that  there  are  specific  diseases,  but  to 
have  fixed  his  attention  rather  on  specific  remedies  than 
specific  causes.  The  latter  were  not  fully  recognized  until 
after  Pasteur's  classic  researches  on  the  specific  microbic 
ferments  of  the  diseases  of  wine  and  beer  (1860-1864). 
After  Thomas  Sydenham  (d.  1689)  "the  reign  of  canonical 
authority  in  medicine  was  at  an  end,  though  the  dogmatic 
spirit  long  survived."  The  philosopher  John  Locke  was 
a  close  friend  of  Sydenham,  and  the  following  quotation 
from  one  of  Locke's  letters  is  noteworthy:  "You  cannot 
imagine  how  far  a  little  observation  carefully  made  by  a 
man  not  tied  up  to  the  four  humors  (Galen),  or  sal, 
sulphur,  and  mercury  (Paracelsus),  or  to  acid  and  alkali 
(Sylvius  and  Willis),  which  have  of  late  prevailed,  will 
carry  a  man  in  the  curing  of  diseases  though  very  stub- 
born and  dangerous ;  and  that  with  very  little  and  common 
things,  and  almost  no  medicine  at  all." 

§  5.  —  Theories  of  the  Eighteenth  Century 

The  theories  of  disease  in  the  eighteenth  century  reflect 
plainly  the  spirit  of  the  times.  On  the  one  hand  we  find 


30          /ETIOLOGY  OR  THE  CAUSES  OF  DISEASE 

views  largely  mechanical,  physical  and  even  astrological; 
and  on  the  other,  an  opposing  series  more  mystical,  ani- 
mistic and  even  spiritualistic.  As  natural  successors  to 
Hippocrates,  Galen  and  Sydenham,  we  find  Boerhaave, 
Haller  and  Morgagni,  while  opposed  to  them  and  as 
natural  successors  to  Paracelsus,  Hoffmann,  Stahl  (author 
of  the  Phlogiston  theory  in  chemistry)  and  Hahnemann, 
—  all  more  or  less  supernaturalists.  The  labors  of  Boer- 
haave, Haller  and  Morgagni  served  to  establish  upon  a 
sure  foundation  our  present  essentially  physical  and  me- 
chanical views  of  constitutional  disease  (see  pp.  1 1,  13),  but 
shed  very  little  light  on  the  class  of  diseases  now  called 
"infections"  (the  fevers,  etc.),  which  run  a  peculiar  definite 
course  and  then  disappear.  But  if  these  diseases  baffled 
the  naturalists  of  the  eighteenth  century,  they  were  still 
less  understood  by  the  supernaturalists,  of  whom  only  one 
(Hahnemann)  has  succeeded  in  making  himself  felt  in  the 
nineteenth  century  by  the  perpetuation  of  a  special  "  sys- 
tem "  typical  of  the  numerous  "  systems  "  of  the  eighteenth 
century. 

§  6.  —  The  Theory  of  Hahnemann 

"  Hahnemann  taught  that  disease  is  to  be  regarded  as 
consisting  especially  of  the  symptoms  of  it  as  experienced 
and  expressed  by  the  patient,  or  as  detected  by  the  physi- 
cian; in  other  words,  that  the  chief  symptoms,  or  the 
'totality  of  the  symptoms,'  constitute  the  disease,  and 
that  disease  is  in  no  case  caused  by  any  material  substance, 
but  is  only  and  always  a  peculiar,  virtual,  dynamic  derange- 
ment of  the  health.  '  Diseases '  (Introduction  to  the 
'  Organon,'  p.  17)  'will  not  cease  to  be  spiritual  dynamic 
derangements  of  our  spiritual  vital  principle.'  He  says 
on  page  3  of  the  '  Organon ' :  '  For  as  far  as  the  greatest 
number  of  diseases  are  of  dynamic  (spiritual)  nature,  their 
cause  is  therefore  not  perceptible  to  the  senses ; '  and  at 
page  1 8,  referring  to  'small-pox,  a  disease  accompanied 


THEORIES   OF   THE   EIGHTEENTH   CENTURY        31 
\ 

by  almost  general  suppuration,'  he  asks,  '  Is  it  possible  to 
entertain  the  idea  of  a  material  morbific  matter  being 
introduced  into  the  blood  ? '  He  held  that  the  psoric 
miasm,  of  which  the  itch  is  the  outward  and  visible  and 
comparatively  harmless  sign,  was  at  the  root  of  nearly  all 
chronic  disease,  viz.,  of  all  chronic  disease  that  was  not  due 
to  syphilis  or  sycosis.  ...  In  all  countries  the  doctrine 
of  homoeopathy  is  still  without  broad  scientific  recogni- 
tion. .  .  .  Hahnemann  despised  any  deep  study  of  disease, 
and  theorized  about  it  instead.  Had  he  carefully  inquired 
into  the  nature  and  natural  history  of  disease  as  Hippo- 
crates did,  or  as  he  himself  inquired  into  the  sensations  of 
those  who  took  infinitesimal  doses,  he  would  have  done 
more  for  the  world  and  his  own  reputation.  Hahnemann 
was  easily  captivated  by  theories,  but  not  very  sound  in 
his  reasoning.  But  underlying  all  his  system,  as  we  have 
seen,  was  the  idea  that  the  causes  of  disease  were  impal- 
pable, immaterial,  spiritual,  dynamic.  And  this  great 
foundation  was  rotten.  Modern  medicine  is  doing  some 
of  its  best  work  in  showing  the  material  and  the  visible 
character  of  the  causes  of  many  of  the  commonest  diseases, 
and  suggests  this  in  many  cases  where  it  has  not  as  yet 
been  demonstrated.  The  cause  of  many  diseases  is  shown 
to  be  a  living  germ  or  particle  which  can  be  discerned 
under  the  microscope,  can  be  carried  on  a  lancet  or  in  a 
tube  and  inserted  under  the  skin  so  as  to  produce  its  pecul- 
iar disease.  .  .  .  The  causes  of  other  diseases  are  often 
not  merely  visible  under  a  microscope,  but  coarsely  visible. 
We  have  been  lately  told,  on  high  authority,  that  to  pro- 
duce certain  forms  of  blood-poisoning  one  or  two  ounces 
at  least  of  septic  fluid  are  necessary.  So  with  other  forms 
of  common  disease.  Alcohol  does  not  destroy  a  liver  or 
kidney  in  any  dynamic  or  immaterial  form,  but  in  coarse 
quantities  diligently  repeated.  The  lead  which  paralyzes 
the  painter's  wrist  is  not  a  '  spiritual '  thing.  It  is  an 
accumulation  of  matter  in  the  wrong  place,  and  enters  his 


32  ETIOLOGY   OR  THE   CAUSES   OF  DISEASE 

body  in  palpable  quantities,  and,  what  is  more,  can  be 
recovered  in  similar  quantities  from  his  body.  So  with 
the  uric  acid  or  its  salts  in  the  blood  of  a  person  who  has 
inherited  his  father's  gout,  and  perhaps  his  port  wine.  It 
is  not  a  '  spiritual '  affair  at  all,  but  can  be  demonstrated 
chemically  and  under  the  microscope.  The  itch,  to  whose 
mysterious  workings  Hahnemann  attributed  two-thirds  of 
the  internal  diseases  of  the  body,  including  mania,  cancer, 
gout,  etc.,  is  easily  demonstrated  to  be  dependent  on  an 
ugly  crab-like  insect,  which  can  be  destroyed  in  a  few 
hours  with  sulphur,  when  there  is  an  end  both  of  it  and 
of  the  itch."  1 

§7.  —  Theories  of  the  Nineteenth  Century 

If  the  eighteenth  century  is  noteworthy  for  its  numerous 
"systems  "of  medical  theory,  the  nineteenth  is  equally 
conspicuous  for  its  distrust  of  "  systems."  This  was  due 
doubtless  in  part  to  the  natural  swing  of  the  pendulum,  but 
whatever  the  cause  may  have  been,  there  was  unquestion- 
ably, in  the  first  part  of  the  century,  a  wholesome  distrust 
of  all  "  systems  "  and  a  return  to  a  study  of  the  "  natural 
history  of  disease,"  what  has  been  called  a  "rational 
empiricism "  serving  as  the  basis  of  medical  practice. 
This  "  return  to  nature  "  was  powerfully  stimulated  and 
facilitated  by  the  rapid  contemporary  development  of 
physical  science,  and  above  all  by  the  invention  of  the 
achromatic  microscope  objective  between  1815  and  1830, 
so  that  the  compound  microscope,  which  had  been  so  im- 
perfect as  to  be  almost  useless,  became  about  1835  a 
powerful  and  altogether  novel  instrument.  Almost  imme- 
diately results  of  capital  importance  were  reached,  for  in 
1837  an  Italian  investigator,  Bassi,  announced  the  dis- 
covery that  muscarding,  a  contagious  disease  of  silkworms, 
previously  not  understood,  is  really  due  to  a  parasitic 

1  J.  Grey  Glover,  M.D.,  on  "  Homoeopathy,"  Encyclopedia  Britannica,  gth 
ed.,  Vol.  XII,  pp.  126-129. 


THEORIES   OF   TO-DAY  33 

fungus.  Two  years  later  the  still  more  startling  discovery 
was  made  by  Schoenlein  that  favus,  or  "  honeycomb  "  of 
the  human  scalp,  a  disease1  long  known,  but  never  under- 
stood, is  really  due  to  a  parasitic  fungus  growing  at  the 
roots  of  the  hair.  At  almost  the  same  moment  botanists 
discovered  that  yeast,  hitherto  regarded  as  a  mysterious 
"ferment,"  is  also  a  microscopic  fungus;  and  the  idea  was 
boldly  advanced  that  fermentation,  which  had  long  been 
held  to  be  one  of  the  causes  of  disease,  was  really  due  to 
microscopic  fungi.  The  new  microscope  was  also  applied 
to  the  study  of  diseased  tissue,  and  immediately  disclosed 
ravages  so  coarse  and  obvious  as  to  compel  the  idea  of 
mechanical  interference  by  palpable  agents  and  to  stimu- 
late further  search  not  only  for  the  footprints  of  disease, 
but  for  the  mysterious  makers  of  those  footprints.  Mean- 
time the  applications  of  physics  and  chemistry  to  physi- 
ology by  Johannes  Muller  and  Wohler,  Marshall  Hall  and 
Liebig,  were  drawing  attention  to  the  mechanical  and 
material  aspects  of  living  things  and  the  modern  concep- 
tion of  the  body  as  a  physical  mechanism  was  becoming 
more  firmly  established.  The  pathologists  likewise  were 
making  extraordinary  progress  in  their  explorations  of  the 
dead,  and  reporting  constantly  fresh  examples  of  mechani- 
cal disturbance  or  interference,  so  that  by  the  middle  of 
the  nineteenth  century  our  theories  of  constitutional  disease 
as  largely  due  to  poor  timber  or  poor  construction  or 
mechanical  breakdown  were  finally  and  probably  forever 
established. 

1  This  is  a  rare  affection  of  the  scalp  and  body  due  to  the  presence  of  a 
fungus  Achorion  Schoenleinii.  The  disease  was  recognized  and  named  by 
Bateman  and  figured  by  Alibert.  But  it  was  not  till  1839  that  Schoenlein 
published  in  Muller's  Archiv  the  discovery  that  the  yellow  crusts  of  Favus 
were  neither  pustular  nor  sebaceous,  but  were  composed  of  the  mycelia  and 
conidia  of  a  parasitic  fungus.  Ringworm  of  the  Scalp  was  only  proved  to 
depend  on  the  presence  of  a  cryptogamic  parasite  in  1844  by  Malmsen,  the 
Swedish  microscopist.  He  named  the  fungus  Trichophyton  tonsurans. 
—  PVE-SMITH,  Lc. 
D 


34  ETIOLOGY   OR  THE  CAUSES   OF  DISEASE 

The  case  was  different,  however,  with  certain  diseases, 
such  as  the  fevers,  which  run  a  definite  course  and  disap- 
pear. These  remained  still  unexplained  and  inexplicable. 
But  their  solution  also  was  at  hand.  The  obscure  phenomena 
of  fermentation,  as  we  have  seen  above,  had  been  claimed 
to  be  closely  connected  with  disease  by  the  iatro-chemical 
school  of  the  seventeenth  century,  and  this  suggestion  had 
apparently  never  been  wholly  lost  sight  of,  though  it  was 
eclipsed  in  the  eighteenth  century  by  the  rapid  development 
of  physiology.  Modern  chemistry  began  to  unfold  itself 
toward  the  close  of  the  eighteenth  century,  and  by  the 
end  of  the  first  half  of  the  nineteenth  century,  when  the 
achromatic  objective  had  been  perfected,  fermentation 
had  assumed  in  the  hands  of  Liebig  great  popular  impor- 
tance. 

In  1837  the  first  serious  attempt  was  made  to  collect 
and  study  the  vital  statistics  of  England,  and  a  classifica- 
tion of  diseases  became  necessary.  For  this  classification 
of  the  various  causes  of  death  the  following  was  at  first 
used :  — 

(1)  Epidemic,  endemic  and  contagious  diseases. 

(2)  Sporadic  diseases. 

(3)  Evident  external  causes. 

Some  years  later  we  find  instead  the  following  classi- 
fication :  — 

(1)  Zymotic  diseases. 

(2)  Constitutional  diseases. 

(3)  Local  diseases. 

(4)  Developmental  diseases. 

(5)  Violence. 

In  other  words,  those  diseases  previously  called  "epi- 
demic, endemic  and  contagious"  are  now  described  as 
"  zymotic  "  ;  and  upon  this  term  we  may  dwell  somewhat 
at  length. 

"  The  diseases  of  this  class  have  been  frequently  spoken 
of  as  fermentations.  .  .  .  The  property  of  communicating 


ORIGIN   OF   THE   TERM   "ZYMOTIC"  35 

their  action,  and  affecting  analogous  transformations  in 
other  bodies,  is  as  important  as  it  is  characteristic  in  these 
diseases,  which  it  is  proposed  therefore  to  call,  in  this 
sense,  'zymotic.'  A  single  word,  such  as  'zymotics,' 
is  required  to  replace  in  composition  the  long  periphrasis 
'  epidemic,  endemic,  and  contagious  diseases '  with  a  new 
name,  and  a  definition  of  the  kind  of  pathological  process 
which  the  name  is  intended  to  indicate.  .  .  .  The  early 
medical  observers  have  directed  attention  to  the  analogies 
zymotic  diseases  have  with  combustion,  fermentation, 
putrefaction,  and  poisoning.  These  analogies  have  been, 
to  a  certain  extent,  confirmed  by  the  researches  of  modern 
chemistry.  .  .  .  This  class  includes  fever,  small-pox,  plague, 
influenza,  cholera,  and  the  other  diseases  which  have  the 
peculiar  character  of  suddenly  attacking  great  numbers  of 
people  at  intervals  in  unfavorable  sanitary  conditions. 
The  diseases  of  this  class  distinguish  one  country  from 
another,  one  year  from  another ;  they  have  formed  epochs 
in  chronology,  and,  as  Niebuhr  has  shown,  have  influ- 
enced not  only  the  fate  of  cities,  such  as  Athens  and 
Florence,  but  of  empires;  they  decimate  armies,  disable 
fleets;  they  take  the  lives  of  criminals  that  justice  has  not 
condemned;  they  redouble  the  dangers  of  crowded  hos- 
pitals ;  they  infest  the  habitations  of  the  poor,  and  strike 
the  artisan  in  his  strength  down  from  comfort  into  help- 
less poverty ;  they  carry  away  the  infant  from  the  mother's 
breast,  and  the  old  man  at  the  end  of  life ;  but  their  direst 
eruptions  are  excessively  fatal  to  men  in  the  prime  and 
vigor  of  age.  Pestilence  and  famine  have  always  ob- 
tained the  special  attention  of  governments ;  and  epidemi- 
cal maladies  have  a  special  claim  now  to  the  attention  of 
the  statist,  inasmuch  as  by  prophylactic  methods,  of  which 
vaccination  is  an  example,  and  by  hygienic  arrangements, 
the  ravages  of  epidemics  may  be  greatly  diminished.  They 
are  more  than  other  diseases  under  public  control,  and 
may  be  diminished  to  a  large  extent  by  sanitary  measures. 


36          ETIOLOGY  OR  THE  CAUSES   OF  DISEASE 

.  .  .  New  names  are  wanted  to  designate  new  groups  of 
phenomena,  and  might  perhaps  be  less  equivocally  desig- 
nated by  letters  of  the  alphabet ;  but  to  assist  the  memory 
words  have  been  employed  which,  by  their  etymology,  will 
suggest  the  group.  We  do  not,  however,  in  any  case 
accept  the  etymological  sense  as  a  definition  or  a  descrip- 
tion of  the  group  of  causes  which  a  name  designates. 
Thus,  parts  of  the  body  undergo  a  specific  transformation 
in  the  diseases  of  the  first  class,  and  they  have  been  desig- 
nated ZYMOTIC  DISEASES  (zymotic?)  in  England,  without 
any  intention  to  imply  that  these  diseases  are  fermenta- 
tions." l 

In  spite  of  Dr.  Farr's  care  not  to  assume  close  simi- 
larity between  fermentations  and  zymotic  disease,2  the 
proof  of  such  similarity  was,  even  as  he  wrote,  about  to 
be  brought  forward  by  Pasteur. 

§  8.  —  The  Germ  Theory  of  Fermentation 

Alcoholic  fermentation  had  been  generally  regarded  as 
a  purely  chemical  or  a  physical  process  until  in  1838 
Cagniard  de  Latour  and  Schwann  showed  that  the  yeast 
which  accompanies  it  is  a  living  plant.  Liebig  met  this 
discovery  with  scorn  and  ridiculed  the  idea  that  yeast 
was  the  cause  rather  than  the  consequence  of  fermenta- 
tion in  an  article  which  Huxley  has  well  called  the  most 
remarkable  that  ever  appeared  in  a  sober  scientific  jour- 
nal. Nevertheless,  though  with  many  hindrances  because 
of  the  powerful  opposition  of  Liebig,  it  slowly  became 

1  "  Vital  Statistics :   A  Memorial  Volume  of  Selections  from  the  Reports 
and  Writings  of  Dr.  William  Farr,"  pp.  246,  249,  253.     London,  1885. 

2  The  reluctance  of  Dr.  Farr  to  connect  zymotic  diseases  with  fermenta- 
tions was  not   exceptional,  and  was  probably  due  in  part  to  the  strenuous 
opposition   of  Liebig  to  that   view.     In   1863,  Sir  Robert  Christison,  in  an 
"  Address  on  Public  Health  "  before  the  Association  for  the  Encouragement 
of  Social  Science  in  Edinburgh,  said  of  zymotic  diseases,  "  They  are  so  called 
from  the   Greek  zyma,  signifying  ferment,  on  account  of  a  rather  fanciful 
resemblance  between  their  origin  and  the  process  of  fermentation." 


PASTEUR'S   STUDIES  ON   BEER  AND   WINE          37 

clear  that  the  germ  theory  of  fermentation  is  true,  and  that 
live  yeast  is  the  real  "  ferment "  of  the  alcoholic  fermen- 
tation. This  biological  theory  was  thoroughly  and  finally 
established  by  Louis  Pasteur  between  1857  and  1863,  and 
almost  immediately  led  to  the  germ  theory  of  disease 
through  its  extension  by  him  to  the  diseases  of  beer  and 
wine,  which  he  traced  to  micro-organisms  other  than  ordi- 
nary yeast  invading  the  fermentable  liquid  and  interfering 
with  the  usual  alcoholic  fermentation  by  producing  unde- 
sirable fermentations  of  their  own.  At  once  it  became 
clear  to  Pasteur  (and  soon  after  to  the  world)  that  specific 
fermentations  are  caused  by  specific  ferments ;  and,  more- 
over, that  a  disease  of  wine  or  beer  may  be,  and  often  is, 
simply  an  undesirable  fermentation  produced  by  an  invad- 
ing ferment  or  germ. 

§  9.  —  The  Germ  or  Zymotic  (Ferment}  Theory  of  Disease 

It  could  hardly  fail  to  occur  to  any  thoughtful  person 
that  if  this  were  true  for  certain  diseases  of  wine  and  beer, 
it  might  well  be  true  also  for  certain  diseases  of  animals;1 
for  if  we  consider  step  by  step  the  course  of  any  familiar 
fermentation  and  then  do  the  same  for  any  familiar  infec- 
tious disease,  we  shall  discover  between  them  a  remarkable 
similarity.  For  this  purpose  we  may  take  the  fermenta- 
tion of  apple  juice,  or  cider,  and  small-pox.  The  juice  of 

1  "  Les  sciences  gagnent  toutes  a  se  prSter  un  mutuel  appui.  Lorsque,  a  la 
suite  de  mes  premieres  communications  sur  les  fermentations,  en  1857-1858, 
on  put  admettre  que  les  ferments  proprement  dits  sont  des  etres  vivants,  que 
des  germes  d'organismes  microscopiques  abondent  a  la  surface  de  tous  les 
objets  dans  1'atmosphere  et  dans  les  eaux,  que  l'hypoth£se  d'une  generation 
spontanee  est  presentment  chimerique,  que  les  vins,  la  biere,  le  vinaigre,  le 
sang,  1'urine,  et  tous  les  liquides  de  Peconomie  n'eprouvent  aucune  de  leurs 
alterations  communes  au  contact  de  1'air  pur,  la  medecine  et  la  chirurgie 
jeterent  les  yeux  sur  ces  clartes  nouvelles.  Un  medecin  francais,  le  Dr. 
Davaine,  fit  la  premiere  application  heureuse  de  ces  principes  a  la  medecine, 
en  1863." — (Pasteur.}  "La  Vie  de  Pasteur,"  par  Rene  Vallery-Radot, 
p.  390.  Paris,  1900. 


38          .ETIOLOGY  OR  THE  CAUSES  OF  DISEASE 

apples  is  hermetically  sealed  and  kept  from  exposure  to  air 
by  the  apple  skin.  In  the  making  of  cider  this  skin  is 
broken,  the  juice  is  pressed  out  and  of  course  exposed 
to  the  air,  to  dust,  to  the  press,  to  the  sides  of  the  vessel 
which  receives  it,  to  the  strainer  through  which  it  passes, 
etc.  At  first,  and  for  some  time,  the  juice  is  sweet,  insipid, 
unfermented,  but  after  some  time  it  is  plain  that  a  change 
is  going  on.  This  change  is  called  the  "  working "  or 
active  fermentation  of  the  apple  juice,  and  a  closer  exami- 
nation will  show  that  it  is  accompanied  by  a  slight  rise  of 
temperature  or  "  heating  "  (which  is  a  familiar  phenomenon 
in  many  fermentations),  as  well  as  by  obvious  chemical 
changes  resulting  in  the  evolution  of  gas  and  the  dis- 
appearance of  sugar,  in  place  of  which  alcohol  makes  its 
appearance,  giving  to  the  whole  process  the  name  of 
"  alcoholic  fermentation."  The  fermentation  of  any  par- 
ticular portion  of  apple  juice,  however,  is  not  indefinitely 
prolonged.  On  the  contrary,  after  a  comparatively  short 
time  the  process  comes  to  an  end,  the  evolution  of  gas 
ceases,  and  rest  supervenes.  Since  Pasteur's  classical 
researches  we  know  that  what  has  really  happened  has 
been,  first,  the  seeding  of  the  apple  juice  by  (wild)  yeast ; 
second,  the  slow  growth  of  this  during  the  quiescent  period ; 
third,  its  active  growth  and  "working"  during  the  time 
of  obvious  fermentation ;  and  fourth,  its  gradual  cessation 
of  activity  during  the  final  period.  In  the  case  of  the 
infectious  disease  known  as  small-pox  the  history  is  usually 
as  follows :  A  susceptible  patient  must  first  be  exposed 
to  the  disease,  perhaps  by  contact  with  a  person  already 
affected,  perhaps  with  clothing,  letters,  food  or  other  ma- 
terials handled  by  such  a  person.  After  such  exposure 
there  is  for  a  time  no  marked  change  ;  but  because  the  dis- 
ease has  been  shown  by  repeated  experience  to  be  never- 
theless gradually  developing,  as  judged  by  the  result  and 
certain  obscure  premonitory  symptoms  afterward  recalled, 
physicians  have  unanimously  agreed  to  name  this  the 


FERMENTATION   AND   INFECTIOUS   DISEASE        39 


period  of  incubation.  Sooner  or  later,  headache,  malaise, 
and  other  troubles  appear,  the  patient  becomes  seriously 
and  obviously  ill,  a  physician  is  called  in,  a  rise  of  tempera- 
ture or  fever  is  discovered,  the  eruption  and  other  marks 
of  small-pox  appear,  and  the  patient  is  plainly  affected  by 
active  disease  accompanied  by  every  indication  of  profound 
disturbance  and  chemical  change.  But  at  last,  if  death  does 
not  supervene,  recovery  ensues,  and  the  patient  gradually 
becomes  free  from  the  disease  by  which  he  was  tempo- 
rarily overcome.  We  may  add  that  the  barrel  of  apple  juice 
can  undergo  the  alcoholic  fermentation  only  once,  and  that 
the  small-pox  patient  likewise,  as  a  rule,  has  the  small-pox 
only  once.  If  now  we  tabulate  side  by  side,  and  in  order, 
the  principal  phenomena  of  an  alcoholic  fermentation  such 
as  that  of  apple  juice,  and  those  of  an  infectious  disease 
such  as  small-pox,  we  shall  discover  a  remarkable  similarity 
between  them. 


A  FERMENTATION 
(Apple  juice) 

Exposure  of  the  juice  to  air, 
dust,  etc. 

Repose  and  then  slow  change. 
(Growth  of  the  ferment.) 

Active  fermentation  or  "work- 
ing.1" Evolution  of  gas  bub- 
bles, change  of  sugar  to 
alcohol.  Rise  of  tempera- 
ture. 

Gradual  cessation  of  fermenta- 
tion. 

No  further  liability  to  alcoholic 
fermentation. 


AN  INFECTIOUS  DISEASE 
(Small-pox) 

1.  Exposure  of  the  patient  to  in- 

fection. 

2.  Incubation.     (Slow  and  insid- 

ious progress  of  the  disease.) 

3.  Active  disease.    Eruption,  dis- 

turbance of  the  usual  func- 
tions. Rise  of  temperature 
or  fever. 

4.  Slow  convalescence  (or  death) . 

5.  Immunity  to  small-pox. 


The  striking  analogy  here  shown  suggests  something 
more.  It  certainly  justifies  the  suspicion  of  relationship, 
and  shows  well  the  natural  fitness  of  the  term  "zymotic" 
(fermentative)  for  that  class  of  diseases  in  which  an  anal- 
ogy so  remarkable  is  manifest. 


40          ETIOLOGY  OR  THE   CAUSES  OF  DISEASE 

In  the  next  chapter  we  shall  obtain  further  indications 
of  close  relationship  between  fermentation  and  disease. 
Meanwhile,  we  cannot  fail  to  observe  that  as  soon  as  it 
was  shown  by  Pasteur  that  the  phases  of  an  alcoholic  fer- 
mentation are  due  to  the  introduction,  growth  and  chemical 
work  of  a  living  ferment  (yeast)  finding  its  way  into  the 
apple  juice  from  the  air,  dust  or  the  outer  skin  of  the 
apple,  it  became  easy  and  natural  to  suspect  that  small-pox 
and  similar  diseases  are  somehow  caused  by  similar  living 
ferments  finding  their  way  into  the  body  of  the  patient. 
Thus  the  "  germ  "  theory  of  fermentation  naturally  led  to 
a  "  germ  "  theory  of  infectious  disease ;  and  movement  in 
this  direction  became  almost  irresistible  when  Pasteur 
soon  after  established  a  fact  of  the  very  first  importance, 
namely,  that  the  diseases  of  wine  and  beer  are  "germ  " 
diseases,  due  to  their  invasion  by,  and  the  growth  within 
them  of,  undesirable  micro-organisms  (bacteria  or  wild 
yeasts). 

General  attention  was  now  drawn  to  the  subject,  and  the 
germ  theory  of  disease  became  very  widely  known  when 
Pasteur,  hitherto  a  mineralogist,  chemist  and  biologist, 
turned  aside  from  his  laboratory  studies  on  the  fermenta- 
tions of  wine,  beer,  vinegar  and  milk,  and,  in  response  to 
an  urgent  call  from  the  French  government,  began  a  per- 
sonal investigation  of  a  widespread  animal  disease,  which 
had  hitherto  baffled  all  inquiry.  This  was  the  famous 
"  silkworm  disease  "  of  which  his  son-in-law,  M.  V.-Radot, 
has  given  us  an  admirable  popular  account.  Inasmuch 
as  this  brilliant  effort  of  Pasteur  was  one  of  the  most 
important  factors  in  drawing  universal  attention  to  the 
germ  theory  of  disease,  and  inasmuch  as  it  is  in  itself  an 
inspiring  example  of  a  scientific  grappling  with  disease, 
we  may  quote  at  some  length  Radot's  graphic  description, 
as  follows :  — 


ZYMOTIC  DISEASES   OF   BEER  AND  WINE  41 

§  10.  — Louis  Pasteur  and  Infectious  Diseases  of  Silk- 
worms J 

"  The  life  of  the  population  of  certain  departments  in  the  South  of 
France  hangs  on  the  existence  of  silkworms.  In  each  house  there  is 
nothing  to  be  seen  but  hurdles,  over  which  the  worms  crawl.  They  are 
placed  even  in  the  kitchens,  and  often  in  well-to-do  families  they  occupy 
the  best  rooms.  In  the  largest  cultivations,  regular  stages  of  these 
hurdles  are  raised  one  above  the  other,  in  immense  sheds,  under  roofs 
of  disjointed  tiles,'. where  thousands  and  thousands  of  silkworms  crawl 
upon  the  litters,  which  they  have  the  instinct  never  to  leave.  Great 
or  small,  the  silkworm-rearing  establishments  exist  everywhere.  When 
people  accost  each  other,  instead  of  saying  '  How  are  you  ? '  they  say 
'  How  are  the  silkworms  ? '  In  the  night  they  get  up  to  feed  them  or  to 
keep  up  around  them  a  suitable  temperature.  And  then  what  anxiety 
is  felt  at  the  least  change  of  weather  !  Will  not  the  mulberry  leaves  be 
wet  ?  Will  the  worms  digest  well  ?  Digestion  is  a  matter  of  great  im- 
portance to  the  health  of  the  worms,  which  do  nothing  all  their  lives  but 
eat !  Their  appetites  become  especially  insatiable  during  the  last  days 
of  rearing.  All  the  world  is  then  astir,  day  and  night.  Sacks  of  leaves 
are  incessantly  brought  in  and  spread  out  on  the  litters.  Sometimes 
the  noise  of  the  worms  munching  these  leaves  resembles  that  of  rain 
falling  upon  thick  bushes.  With  what  impatience  is  the  moment  waited 
for  when  the  worms  arrive  at  the  last  moulting  !  Their  bodies  swollen 
with  silk,  they  mount  upon  the  brambles  prepared  for  them,  where  they 
shut  themselves  up  in  their  golden  prisons  and  become  chrysalides. 
What  days  of  rejoicing  are  those  in  which  -the  cocoons  are  gathered ; 
when,  to  use  the  words.-ef  Olivier  de  Serres,  the  silk  harvest  is  garnered 
in  !  ... 

"In  the  epidemic  which'  ravaged  the  silkworm  nurseries  in  1849,  the 
symptoms  were  numerous  and  changeable.  Sometimes  the  disease 
exhibited  itself  immediately.  Many  of  the  eggs  were  sterile,  or  the 
worms  died  during  the  first  days  of  their  existence.  Often  the  hatch- 
ing was  excellent,  and  the  worms  arrived  at  their  first  moulting,  but 
that  moulting  was  a  failure.  A  great  number  of  the  worms,  taking  little 
nourishment  at  each  repast,  remained  smaller  than  the  others,  having 
a  rather  shining  appearance  and  a  blackish  tint.  Instead  of  all  the 
worms  going  through  the  phases  of  this  first  moulting  together,  as  is 
usually  the  case  in  a  batch  of  silkworms,  they  began  to  present  a  marked 
inequality,  which  displayed  itself  more  fcnd  more  at  each  successive 

1  "  Louis  Pasteur :  His  Life  and  Labors."  By  his  Son-in-Law.  Trans- 
lated by  Lady  Claud  Hamilton.  P.  127  et  seq.  N.Y.,  Appleton,  1885. 


42          ETIOLOGY   OR  THE  CAUSES   OF  DISEASE 

moulting.  Instead  of  the  worms  swarming  on  the  tables,  as  if  their 
number  was  uniformly  augmenting,  empty  spaces  were  everywhere 
seen ;  every  morning  corpses  were  collected  on  the  litters. 

"  Sometimes  the  disease  manifested  itself  under  still  more  painful 
circumstances.  The  batch  would  progress  favorably  to  the  third,  and 
even  to  the  fourth  moulting,  the  uniform  size  and  the  health  of  the 
worms  leaving  nothing  to  be  desired ;  but  after  the  fourth  moulting  the 
alarm  of  the  husbandman  began.  The  worms  did  not  turn  white,  they 
retained  a  rusty  tint,  their  appetite  diminished,  they  even  turned  away 
from  the  leaves  which  were  offered  to  them.  Spots  appeared  on  their 
bodies,  black  bruises  irregularly  scattered  over  the  head,  the  rings,  the 
false  feet,  and  the  spur.  Here  and  there  dead  worms  were  to  be  seen. 
On  lifting  the  litter,  numbers  of  corpses  would  be  found.  Every  batch 
attacked  was  a  lost  batch.  In  1850  and  1851  there  were  renewed  fail- 
ures. Some  cultivators,  discouraged,  attributed  these  accidents  to  bad 
eggs,  and  got  their  supplies  from  abroad. 

"At  first  everything  went  as  well  as  could  be  wished.  The  year 
1853,  in  which  many  of  these  eggs  were  reared  in  France,  was  one  of 
the  most  productive  of  this  century.  As  many  as  twenty-six  millions 
of  kilogrammes  of  cocoons  were  collected,  which  produced  a  revenue 
of  130,000,000  francs.  But  the  year  following,  when  the  eggs  produced 
by  the  moths  of  these  fine  crops  of  foreign  origin  were  tried,  a  singular 
degeneracy  was  immediately  recognized.  The  eggs  were  of  no  more 
value  than  the  French  eggs.  It  was,  in  fact,  a  struggle  with  an  epi- 
demic. How  was  it  to  be  arrested  ?  Would  it  be  always  necessary  to 
have  recourse  to  foreign  seed  ?  And  what  if  the  epidemic  spread  into 
Italy,  Spain,  and  the  other  silk-cultivating  countries  ? 

"  The  thing  dreaded  came  to  pass.  The  plague  spread  ;  Spain  and 
Italy  were  smitten.  It  became  necessary  to  seek  for  eggs  in  the  Islands 
of  the  Archipelago,  in  Greece,  or  in  Turkey.  These  eggs,  at  first  very 
good,  became  infected  in  their  turn  in  their  native  country ;  the  epi- 
demic had  spread  even  to  that  distance.  The  eggs  were  then  procured 
from  Syria  and  the  provinces  of  the  Caucasus.  The  plague  followed 
the  trade  in  the  eggs.  In  1864  all  the  cultivations,  from  whatever  cor- 
ner of  Europe  they  came,  were  either  diseased  or  suspected  of  being  so. 
In  the  extreme  East,  Japan  alone  still  remained  healthy. 

"  Agricultural  societies,  governments,  all  the  world,  were  preoccupied 
with  this  scourge  and  its  invading  march.  It  was  said  to  be  some 
malady  like  cholera  which  attacked  the  silkworms.  Hundreds  of  pam- 
phlets were  published  each  year.  The  most  foolish  remedies  were  pro- 
posed, as  quite  infallible,  —  from  flowers  of  sulphur,  cinders,  and  soot 
spread  over  the  worms,  or  over  the  leaves  of  the  mulberry,  to  gaseous 
fumigations  of  chlorine,  of  tar,  and  of  sulphurous  acid.  Wine,  rum, 


AN   INFECTIOUS   DISEASE   OF   SILKWORMS          43 

absinthe,  were  prescribed  for  the  worms,  and  after  the  absinthe  it  was 
advised  to  try  creosote  and  nitrate  of  silver.  In  1863  the  Minister  of 
Agriculture  signed  an  agreement  with  an  Italian  who  had  offered  for 
purchase  a  process  destined  to  combat  the  disease  of  the  silkworms,  by 
which  he  (the  Minister)  engaged  himself,  in  case  the  efficacy  of  the 
remedy  was  established,  to  pay  500,000  francs  as  an  indemnity  to  the 
Italian  silk  cultivator.  Experiments  were  instituted  in  twelve  depart- 
ments, but  without  any  favorable  result.  In  1865  the  weight  of  the 
cocoons  had  fallen  to  four  million  kilogrammes.  This  entailed  a  loss 
of  100,000,000  francs. 

"  The  Senate  was  assailed  by  a  despairing  petition  signed  by  thirty- 
six  hundred  mayors,  municipal  councillors,  and  capitalists  of  the  silk- 
cultivating  departments.  The  great  scientific  authority  of  M.  Dumas, 
his  knowledge  of  silk  husbandry,  his  sympathy  for  one  of  the  depart- 
ments most  severely  smitten,  the  Card,  his  own  native  place,  all  con- 
tributed to  cause  him  to  be  nominated  Reporter  of  the  Commission. 
While  drawing  up  his  report  the  idea  occurred  to  him  of  trying  to  per- 
suade Pasteur  to  undertake  researches  as  to  the  best  means  of  combat- 
ing the  epidemic. 

"  Pasteur  at  first  declined  this  offer.  It  was  at  the  moment  when 
the  results  of  his  investigations  on  organized  ferments  opened  to  him  a 
wide  career ;  it  was  at  the  time  when,  as  an  application  of  his  latest 
studies,  he  had  just  recognized  the  true  theory  of  the  manufacture  of 
vinegar,  and  had  discovered  the  cause  of  the  diseases  of  wines ;  it  was, 
in  short,  at  the  moment  when,  after  having  thrown  light  upon  the  ques- 
tion of  spontaneous  generation,  the  infinitely  little  appeared  infinitely 
great.  He  saw  living  ferments  present  everywhere,  whether  as  agents 
of  decomposition  employed  to  render  back  to  the  atmosphere  all  that 
had  lived,  or  as  direct  authors  of  contagious  diseases.  And  now  it  was 
proposed  to  him  to  quit  this  path,  where  his  footing  was  sure,  which 
offered  him  an  unlimited  horizon  in  all  directions,  to  enter  on  an 
unknown  road,  perhaps  without  an  outlet.  Might  he  not  expose  him- 
self to  the  loss  of  months,  perhaps  of  years,  in  barren  efforts  ? 

"  M.  Dumas  insisted.  '  I  attach,1  said  he  to  his  old  pupil,  now 
become  his  colleague  and  his  friend,  '  an  extreme  value  to  your  fixing 
your  attention  upon  the  question  which  interests  my  poor  country.  Its 
misery  is  beyond  anything  that  you  can  imagine.' 

" '  But  consider,'  said  Pasteur,  •'  that  I  have  never  handled  a  silk- 
worm.' 

"'So  much  the  better,'  replied  M.  Dumas.  'If  you  know  nothing 
about  the  subject,  you  will  have  no  other  ideas  than  those  which  come 
to  you  from  your  own  observations.' 

"  Pasteur  allowed  himself  to  be  persuaded  .  .  .  and  on  June  6, 1865, 


44          /ETIOLOGY   OR   THE   CAUSES   OF  DISEASE 

started  for  Alais.  The  emotion  he  felt  on  the  actual  spot  where  the 
plague  raged  in  all  its  force,  in  the  presence  of  a  problem  requiring 
solution,  caused  him  at  once  to  forget  the  sacrifices  he  had  made  in 
quitting  his  laboratory  at  the  Ecole  Normale.  He  determined  not  to 
return  to  Paris  until  he  had  exhausted  all  the  subjects  requiring  study, 
and  had  triumphed  over  the  plague. 

"  One  of  the  most  recent  and  the  most  comprehensive  memoirs  upon 
the  terrible  epidemic  had  been  presented  to  the  Academy  of  Sciences 
by  M.  de  Quatrefages.  One  paragraph  of  this  paper  had  forcibly  struck 
Pasteur.  M.  de  Quatrefages  related  that  some  Italian  naturalists  .  .  . 
had  discovered  in  the  worms  and  moths  of  the  silkworm  minute  cor- 
puscles visible  only  with  the  microscope.  .  .  .  This  instrument  had 
already  rendered  such  services  to  Pasteur  in  his  delicate  experiments  on 
ferments  that  he  was  fascinated  by  the  thought  of  resuming  it  again  as 
an  instrument  of  research.  .  .  . 

"  In  a  few  hours  after  his  arrival  he  had  already  proved  the  presence 
of  corpuscles  in  certain  worms,  and  was  able  to  show  them  to  the  Presi- 
dent and  several  members  of  the  Agricultural  Committee,  who  had 
never  seen  them.  .  .  . 

"It  was  necessary  to  know  if  there  existed  the  relation  of  cause  and 
effect  between  the  corpuscles  and  the  disease.  This  was  the  great  point 
to  be  elucidated.  .  .  . 

"  One  of  the  first  cares  of  Pasteur  was  to  settle  the  question  as  to  the 
contagion  of  the  disease.  Many  hypotheses  had  been  formed  regarding 
this  contagion,  but  few  experiments  had  been  made,  and  none  of  them 
were  decisive.  Opinions,  also,  were  very  much  divided.  .  .  . 

"  But  whatever  the  divergences  of  opinion  might  be,  every  one,  at  all 
events,  believed  in  the  existence  of  a  poisonous  medium  rendered  epi- 
demic by  some  occult  influence.  Pasteur  soon  succeeded,  by  accurate 
experiments,  in  proving  absolutely  that  the  evil  was  contagious.  .  .  . 
All  the  disasters  that  were  known  to  have  happened  in  the  silkworm 
nurseries,  their  extent  and  their  varied  forms,  were  faithfully  reproduced. 
Pasteur  created  at  will  any  required  manifestation  of  the  disease.  .  .  . 

"  For  five  years  Pasteur  returned  annually  for  some  months  to  Alais. 
The  little  house  nestling  among  the  trees,  called  Pont-Guisket,  became 
at  the  same  time  his  habitation  and  his  silkworm  nursery.  .  .  . 


"  All  the  obscurity  which  enveloped  the  origin  of  the  diseases  of  silk- 
worms had  now  been  dispelled.  Pasteur  had  arrived  at  such  accurate 
knowledge  both  of  the  causes  of  the  evil  and  their  different  manifesta- 
tions, that  he  was  able  to  produce  at  will  either  ptbrine  w  flacker  ie.  He 
could  so  regulate  the  intensity  of  the  disease  as  to  cause  it  to  appear  on 


PASTEUR'S   PERSISTENCE   AND   VICTORY  45 

a  given  day,  almost  at  a  given  hour.  .  .  .  To  triumph  over  this  disease 
(pebrine),  which  was  so  threatening,  Pasteur  devised  a  series  of  obser- 
vations as  simple  as  they  were  ingenious.  .  .  .  This  process  of  pro- 
curing sound  eggs  is  now  universally  adopted.  .  .  . 


"  But  if  Pasteur  brought  back  wealth  to  ruined  countries,  if  he  had 
returned  to  Paris  happy  in  the  victory  he  had  gained,  he  had  also  under- 
gone such  fatigues,  and  had  so  overstrained  himself  in  the  use  of  the 
microscope  while  absorbed  in  his  daily  and  varied  experiments,  that  in 
October,  1868,  he  was  struck  with  paralysis  of  one  side.  Seeing,  as  he 
thought,  death  approaching,  he  dictated  to  his  wife  a  last  note  on  the 
studies  which  he  had  so  much  at  heart.  This  note  was  communicated 
to  the  Academy  of  Sciences  eight  days  after  this  terrible  trial. 

"  A  soul  like  his,  possessing  so  great  a  mastery  over  the  body,  ended 
by  triumphing  over  the'  affliction.  Paralyzed  on  the  left  side,  Pasteur 
never  recovered  the  use  of  his  limbs.  To  this  day  (1884),  sixteen  years 
after  the  attack,  he  limps  like  a  wounded  man." 

§  ii.  —  Sir  Joseph  (now  Lord}  Lister  and  Infectious  Dis- 
eases of  Wounds.     Sanitary  (Aseptic)  Siirgery 

Stirred  by  the  investigations  of  Pasteur,  and  reflecting 
upon  their  significance,  Sir  Joseph  Lister,  already  an 
eminent  surgeon  of  Edinburgh,  became  convinced  that 
many  wound  diseases  are  probably  infectious  and,  if  so, 
preventable.  Accordingly,  he  set  to  work,  and  by  the 
use  of  antiseptic  dressings,  sprays,  instruments,  etc.,  soon 
established  his  thesis  and  paved  the  way  for  the  modern 
practice  of  sanitary  or  aseptic  surgery,  which  was  not  only 
the  first-fruit,  but  is  also  hitherto  the  most  brilliant  of  the 
triumphs,  of  the  germ  theory  of  infectious  disease.  By 
its  aid  surgery  has  been  not  only  revolutionized  but  also 
vastly  extended.  Operations  formerly  dreaded  are  now 
done  with  perfect  assurance  and  constant  success.  The 
operating  rooms  of  hospitals  are  built  and  conducted 
almost  solely  with  reference  to  the  exclusion  or  control 
of  those  micro-organisms  (germs)  which  are  now  univer- 
sally recognized  as  the  principal  enemies  of  the  patient 
and  the  worst  foes  of  the  surgeon. 


CHAPTER   III 

ON  THE  RISE  AND  INFLUENCE  OF  BACTERIOLOGY.  TRANS- 
FORMATION OF  THE  ZYMOTIC  INTO  THE  ZYMOTOXIC  THEORY 
OF  INFECTIOUS  DISEASE 

"  Within  the  world  of  life  to  which  we  ourselves  belong  there  is 
another  living  world,  requiring  the  microscope  for  its  discernment,  but 
which,  nevertheless,  has  the  most  important  bearing  on  the  welfare  of 
the  higher  life-world."  —  TYNDALL. 

"In  der  Aussenwelt,  welche  die  alltagliche  Umgebung  des  Menschen 
bildet  und  den  Gegenstand  der  hygienischen  Forschung  ausmacht,  findet 
der  aufmerksame  Beobachter  in  weitester  Verbreitung  Organismen,  die 
an  der  Grenze  der  Sichtbarkeit  stehen,  selbst  fur  das  mit  besten  opti- 
schen  Hiilfsmitteln  geriistete  Auge,  die  aber  mit  ihrer  ungeahnt  aus- 
gedehnten,  tief  eingreifenden  Thatigkeit  eine  hochwichtige  Rolle  im 
Haushalt  der  Natur  und  im  Dasein  des  Menschen  spielen.  Sie  bewirken 
die  Zerstorung  lebloser  organischer  Substanz,  .  .  .  sie  erregen  die  ver- 
schiedensten  Gahrungen  und  sind  uns  unersetzliche  Hiilfsmittel  zur 
Bereitung  unserer  gewohnten  Nahrungs-  und  Genussmittel ;  sie  be- 
fallen andererseits  unsere  Culturgewachse  als  Parasiten,  die  ihren 
Wirthen  Degeneration  und  Tod  bringen ;  sie  veranlassen  gelegentlich 
schwerste  Erkrankungen  bei  niederen  und  hoheren  Thieren,  und  selbst 
den  Menschen  bedrohen  sie  mit  morderischen  Epidemien." 

—  FLUGGE. 

§  I. —  The  Achromatic  Microscope  Objective 

REFERENCE  was  made  in  the  last  chapter  to  the  influence 
of  the  newly  discovered  achromatic  microscope  objective 
upon  the  development  of  the  germ  theory  of  fermentation 
and  its  corollary  the  germ  theory  of  disease.  Its  aid  was 
also  now  being  felt  from  a  somewhat  different  direction, 
namely,  from  purely  zoological  and  botanical  studies  of  the 
lowest  forms  of  life.  Pasteur's  studies  on  wine  and  beer, 

46 


EXPLORATION   OF   THE   MICROSCOPIC   WORLD       47- 

on  the  "  organized  corpuscles  "  of  the  air,  and  on  the  dis- 
eases of  wine,  beer  and  silkworms,  had  pointed  downward 
into  the  world  of  the  "  infinitely  little  "  as  the  source  of 
those  "germs"  of  life  which  seemed  so  small  and  yet  so 
potent  in  fermentation  and  disease.  All  eyes,  therefore, 
were  turned  in  that  direction,  and  extreme  interest  and 
curiosity  were  felt  to  know  all  that  could  be  learned  of  the 
lowest  forms  of  life,  popularly  described  as  "  germs."  This 
interest  and  curiosity  were  intensified,  no  doubt,  by  the 
rise  just  at  this  time  of  Darwinism,  which  also  pointed 
downward  for  the  beginnings  of  organic  species  to  equally 
mysterious  microscopic  and  primitive  "  germs  "  of  life.  As 
a  result  of  these  various  inquiries  one  group  of  micro-organ- 
isms or  germs,  the  Bacteria,  then  only  recently  studied  by 
botanists,  and  lately  located  in  the  vegetable  kingdom, 
became  and  has  ever  since  remained  of  the  first  impor- 
tance to  sanitarians  and  setiologists. 

§  2. — Animalcula,  Vibrionia,  Bacteria 

The  compound  microscope  is  believed  to  have  been 
invented  about  the  middle  of  the  seventeenth  century,  and 
micro-organisms,  some  of  which  were  probably  bacteria, 
were  seen  by  Kircher  (1650),  figured  by  Leeuwenhoek 
(1680)  and,  because  they  were  capable  of  motion,  received 
as  a  group  the  name  Thierchen  or  animalcula,  i.e.  "  little 
animals  "  or  "  animalcules."  The  compound  microscope 
of  the  seventeenth  century,  however,  was  a  very  poor 
instrument  and  that  of  the  eighteenth  century  little,  if 
any,  better.  The  best  evidence  of  these  facts  is  that  many 
microscopists  actually  abandoned  the  use  of  the  compound 
microscope  of  the  day,  preferring  the  simple  microscope 
of  lower  power  but  comparative  freedom  from  aberrations 
to  the  compound  instrument  of  the  time  with  its  colored 
and  distorted  images.  We  need  not  be  surprised,  there- 
fore, to  learn  that  the  microscopists  of  the  eighteenth 


48          RISE   AND   INFLUENCE   OF   BACTERIOLOGY 

century  made  but  small  progress  in  the  territory  of  the 
"  animalcules."  The  first  important  and  extensive  advance 
upon  the  work  of  Leeuwenhoek  was  made  a  hundred  and 
fifty  years  later,  and  with  the  aid  of  the  newly  discovered 
achromatic  objective,  by  Ehrenberg  (1838)  and  his  con- 
temporaries. The  vast  horde  of  forms  originally  called 
"  animalcules  "  had,  it  is  true,  by  this  time  been  separated 
into  two  or  three  main  divisions,  only  one  of  which  is  of 
consequence  to  us,  namely,  the  Vibrionia,  a  group  of  the 
infusorial  animalcules  ;  and  in  1850  the  suspicion  for  the 
first  time  found  expression  that  these  are  not  all,  or  neces- 
sarily, animal  forms,  for  in  that  year  a  young  physician  of 
Boston,  Dr.  Waldo  Irving  Burnett,  read  before  the  Amer- 
ican Association  for  the  Advancement  of  Science  a  paper 
entitled  "The  Family  of  Vibrionia (Ehrenberg)  not  Animals 
but  Plants."  His  proofs  were  unsatisfactory,  but  the 
idea  steadily  grew  until  in  1857  Nageli,  the  distinguished 
botanist  of  Munich,  definitely  and  finally  classified  the 
Vibrionia  as  plants,  giving  to  them  the  name  of  Schizo- 
mycetes  —  "fission  plants."  To  show  that  the  earlier 
names  still  prevailed  for  a  time,  however,  we  need  only 
mention  the  fact  that  Pasteur  in  his  earlier  papers  fre- 
quently refers  to  these  forms  as  "  infusorial  animalcules  " 
or  "  corpuscles."  A  long  step  forward  was  made  when,  in 
1872,  Ferdinand  Cohn,  of  Breslau,  began  the  publication 
of  a  series  of  papers  entitled  "  Investigations  on  Bac- 
teria." 1  From  that  time  onward  the  word  "  bacteria  "  has 
largely  replaced  the  term  "germs"  in  England,  America 
and  Germany.  In  France  the  term  "  microbes "  seems 
to  be  preferred,  and  much  can  be  urged  in  its  favor.  A 
synonym  for  this  is  extensively  used  in  Germany,  Great 
Britain  and  America,  namely,  "  micro-organisms."  Both 
terms  are  useful  as  including  animal  as  well  as  plant  forms ; 
and  all  of  these  terms  may  be  said  to  be  partial  modern 
equivalents  of  the  older  term  "  animalcules."  All  of  them 

1  "Untersuchungen  uber  Bacterien,"  Beitrage  zur  Biologie. 


GERMS,  MICROBES,  MICRO-ORGANISMS,  BACTERIA     49 

include  living  "  ferments  "  capable  of  producing  profound, 
though  often  invisible,  changes  in  organic  substances,  and 
of  causing  singly  or  in  cooperation  those  mysterious  pro- 
cesses called  fermentation,  putrefaction,  decay  and  some- 
times infectious  disease.  The  bacteria  alone  belong  exclu- 
sively to  the  vegetable  kingdom. 

§  3.  —  The  Foundations  of  Bacteriology  laid  by  Louis 
Pasteur 

It  has  already  been  told  in  the  previous  chapter  how  the 
labors  of  Louis  Pasteur  served  to  establish  the  "  germ  " 
theory  of  fermentation  and  prepared  the  way  for  a  "germ" 
theory  of  disease.  His  labors  bore  fruit  also  by  laying  for 
all  time  the  secure  foundations  of  what  has  since  come  to 
be  a  new  branch  of  science,  namely,  bacteriology.  Pasteur 
was  not  the  first  to  use  the  microscope  in  studies  on  fer- 
mentation, but  he  was  the  first  to  employ  careful  culti- 
vations of  the  micro-organisms  concerned,  and  special 
importance  belongs  to  his  constant  attempts  to  secure 
"  pure  cultures  "  of  yeast  and  other  living  ferments.  It 
is  true  that  he  was  compelled  to  rely  altogether  upon  liquid 
cultivation,  so  that  the  actual  purity  of  his  cultures  is  open 
to  some  question ;  but  there  is  no  doubt  whatever  that  by 
his  ingenious  and  successful  use  of  these  so-called  "  pure 
cultures" — which  led  him  to  the  discovery  of  specific 
causative  germs  in  certain  specific  diseases  of  wine  and 
beer,  as  well  as  in  normal  fermentations,  such  as  the  acetic 
and  lactic,  not  to  mention  the  specific  "  corpuscles  "  of  the 
silkworm  diseases,  —  Pasteur  earned  the  high  privilege  of 
being  regarded  as  the  "founder"  of  bacteriology.  It  may 
be  well  to  state  at  this  point,  by  way  of  anticipation  and  in 
order  to  avoid  misunderstanding,  that  the  honor  of  estab- 
lishing bacteriology  as  a  science  upon  the  foundation  laid 
by  Pasteur,  belongs  to  Robert  Koch,  who,  by  proving  (in 
1876)  that  bacteria  are  the  cause  and  not  the  consequence 


50         RISE  AND   INFLUENCE  OF   BACTERIOLOGY 

of  a  particular  disease  (anthrax)  and  by  introducing  (in 
1881)  an  indispensable  method  of  cultivation — the  method 
of  "solid"  as  opposed  to  "liquid"  cultures  —  raised  bac- 
teriology from  a  previously  dubious  position  to  one  of 
high  honor  among  the  biological  sciences. 

§  4.  —  Micro-organisms  the  Cause  and  not  merely  tJie 
Consequence  of  Disease 

The  germ  theory  of  disease  was  not  without  strenuous 
opponents.  In  particular,  the  objection  was  raised  that 
there  was  as  yet  no  evidence  that  the  germs  observed  in 
any  disease  might  not  have  been  caused  by  the  disease 
itself,  they  being  the  consequence  and  not  the  cause  of  it 
This  was  really  a  sound  and  valid  objection.  It  had  been 
successfully  raised  by  Liebig  against  Cagniard  de  Latour 
and  Schwann,  the  discoverers  of  yeast  as  a  living  fer- 
ment, as  early  as  1839,  and  had  been  silenced  in  the 
case  of  Pasteur's  studies  on  fermentation  only  with  diffi- 
culty and  by  means  of  his  use  of  needle  inoculations  and 
practically  pure  liquid  cultivations.  It  was  now  (1865- 
1875)  urged  with  reason  and  with  vehemence  because 
many  absurd  claims  were  being  made  regarding  the  dis- 
covery of  the  "  germs "  of  various  diseases,  based  upon 
mere  observation  of  microbes  in  the  bodies  of  persons  suf- 
fering from  those  disorders  or  else  detected  in  their  food 
or  drink.  In  such  a  case  it  was  entirely  possible  for  any 
one  to  urge  that  the  patient  had  first  fallen  ill  and  had  then 
been  invaded  by  the  germs,  the  disease  being  primary  and 
the  germs  purely  secondary  and  adventitious.  This  view 
was  forever  disproved,  and  bacteriology  for  the  first  time 
established  on  a  scientific  basis  by  the  splendid  researches 
of  Robert  Koch  upon  splenic  fever,  or  anthrax,  between 
1875  and  1878.  Koch  was  a  young  physician  of  Woll- 
stein,  in  Prussia,  when  he  began  his  studies  on  anthrax. 
This  disease  is  not  rare  in  Germany,  Russia  and  other 


CULTIVATION  OF  SPLENIC  FEVER  GERMS          51 

parts  of  Europe,  and  affects  mainly  cattle,  sheep  and 
horses,  but  also,  at  times,  human  subjects.  On  examining 
the  bodies  of  cattle  dead  of  anthrax,  Koch  found  with  the 
microscope  (as  Davaine  in  1859  and  others  before  him  had 
found)  minute  rods  or  sticks  in  the  blood  and  other  organs, 
and  especially  in  the  spleen.  To  some  observers  this  had 
seemed  enough  to  prove  that  these  were  the  "germs"  of 
the  disease ;  but  Koch  did  not  rest  here.  Following  the 
methods  already  employed  by  Pasteur  in  his  researches  on 
yeast,  Koch  transferred  a  needleful  of  blood  or  other  tissue 
charged  with  the  mysterious  rods  to  a  relatively  large  por- 
tion of  the  clear  normal  liquid  which  constitutes  the  aque- 
ous humor  of  the  ox's  eye.1  After  a  few  days,  or  even 
hours,  the  rods,  being  alive  and  able  to  grow  in  this  liquid, 
had  multiplied  enormously,  while  the  portion  of  tissue 
carried  over  with  them  being  dead  had  not  increased  but 
rather  diminished.  From  this  first  dish  a  needleful  was 
now  similarly  transferred  to  a  second  large  and  fresh  por- 
tion of  aqueous  humor,  which  was  thus  seeded  in  its  turn. 
From  this  second  a  third  was  eventually  seeded,  and  so 
on.  A  little  reflection  will  show  that  at  each  transplanting, 
though  many  of  the  rods  were  carried  over,  very  little,  and 
always  less  and  less,  of  the  original  tissue  was  transferred. 
Moreover,  the  rods  transplanted  soon  included  few  or  none 
of  the  original  rods  derived  from  the  diseased  animal,  but 
only  the  innumerable  descendants  of  these  in  more  and 
more  remote  generations.  It  is  easy  to  see  that  after  a 
number  of  transplantings  not  only  none  of  the  original 
diseased  tissue  could  have  remained  —  those  things  only 
being  represented  that  had  the  power  of  life,  growth  and 
reproduction,  but  also  none  of  the  original  "  germs."  This 
method  of  cultivating  the  living  plants  —  for  the  rods  are 

1  If  it  be  asked  how  he  hit  upon  the  use  of  this  liquid,  the  answer  is  that 
such  transparent  liquids  had  often  been  used  in  the  study  of  animal  tissues 
(histology),  being  known,  because  of  their  occurrence  normally  in  the  animal 
body,  as  "  normal  "  fluids. 


52          RISE   AND   INFLUENCE   OF   BACTERIOLOGY 

plants  —  was  clearly  a  kind  of  horticulture,  and  it  has  be- 
come known  as  the  method  of  liquid  "cultures."  It  should 
not  be  forgotten  that  it  was  first  used  successfully  (for  yeast) 
by  Louis  Pasteur.  If  as  a  result  of  its  use  only  one  kind 
of  micro-organism  (yeast,  bacterium)  finally  remains,  such 
a  culture  is  said  to  be  "pure,"  or  "a  pure  culture"  ;  pre- 
cisely as  a  wheat  field  free  from  everything  but  wheat 
would  be  a  "  pure  culture  "  of  wheat.  Moreover,  just  as 
the  ripe  grains  of  wheat  in  a  wheat  field  are  not  those  which 
were  planted  but  only  their  offspring,  so  the  rods  in  Koch's 
cultures  of  the  third  or  tenth  generation  were  not  those 
originally  sown  by  the  needle  or  directly  derived  from  the 
diseased  animals.  But  if  the  rods  so  derived  really  caused 
the  disease  known  as  anthrax,  then  their  own  offspring 
might  reasonably  be  expected  to  have  similar  properties 
and  powers,  precisely  as  wheat  grains  have  the  properties 
of  the  seed  wheat.  Accordingly,  Koch  proceeded  to  in- 
oculate healthy  susceptible  animals  with  his  pure  cultures 
of  anthrax  rods,  rightly  thinking  that  if  these  were  the 
germs  of  the  disease  they  should  be  able  to  reproduce  it. 
The  result  was  perfectly  conclusive :  the  inoculated  animals 
promptly  died  of  typical  anthrax,  and  proof  now  existed, 
for  the  first  time  in  the  history  of  pathology,  that  a  specific 
germ  was  and  is  the  cause,  and  not  merely  the  accompani- 
ment or  the  consequence,  of  at  least  one  well-known  speci- 
fic, infectious  disease. 

An  immediate  result  of  this  brilliant  work  of  Koch  was 
to  give  a  fresh  stimulus  to  the  study  of  the  bacteria,  already 
in  full  cry  since  the  beginning  of  the  classic  researches  of 
Cohn,  who,  in  1875,  added  to  his  earlier  results  the  highly 
important  discovery  that  some  bacteria  can,  and  under 
certain  circumstances  do,  produce  spores  which  appear  to 
be  protective,  highly  tenacious  of  life,  and  very  resistant  to 
destruction  by  drying,  heat,  poisons,  etc.  Moreover,  Koch 
not  only  readily  discovered  spores  in  the  rods  of  anthrax, 
but  also  succeeded,  as  only  a  very  few  observers  had  done 


CRUCIAL   TESTS   ON   LIVING  ANIMALS  53 

before  him,  in  finding  on  other  germs — notably  certain  large 
spiral  forms  in  ditch  water — cilia  or  lashes  in  active  motion 
and  presumably  locomotor  in  function.  These  he  (for  the 
first  time,  in  1877)  even  succeeded  in  photographing.1 

§  5. — A  New  Method  of  cultivating  Bacteria  and  the 
Establishment  of  Bacteriology  as  a  recognised  Biologic 
Science  by  Robert  Koch  in  1881. 

Bacteria  were  probably  first  discovered  in  the  latter  part 
of  the  seventeenth  century  by  Kircher  and  Leeuwenhoek, 
as  has  been  stated  already,  but  it  was  not  until  1857  that 
microscopists  were  able  satisfactorily  to  classify  them  as 
plants,  and  definitely  locate  them  in  the  natural  system. 
Pasteur  observed  many  of  them,  for  example  a  lactic 
ferment,  a  vinegar  ferment  and  certain  disease  ferments 
of  wine,  beer,  etc.,  and  his  work  on  these  ferments,  as  well 
as  on  yeast,  and  especially  his  use  of  the  method  of  "pure" 
liquid  cultures,  constitutes  the  basis  of  the  modern  science 
of  bacteriology,  no  less  than  that  of  the  germ  theory  of 
disease.  Pasteur  is,  therefore,  undoubtedly  entitled  to  be 
known  as  the  founder  of  bacteriology.  And  yet,  owing  to 
the  intrinsic  and  peculiar  difficulties  of  the  subject,  but 
little  headway  was  made  in  exact  knowledge  of  the  bacte- 
ria themselves,  and  bacteriology  as  a  distinct  science  was 
not  established  until,  in  1881,  a  new  and  vastly  improved 
method  of  cultivating  bacteria  was  introduced  by  Robert 
Koch.  This  method,  while  extremely  simple,  was  yet  so 
effective  and  so  fruitful  that  it  forthwith  became  indis- 
pensable to  many  researches  in  biology. 

The  method  of  cultivation  which  immediately  proved  so 
valuable  is  familiar  to  all  biologists  and  is  known  as 
"Koch's  method  of  solid  cultures."  Up  to  1881  all  cul- 
tures of  yeast  or  bacteria  hitherto  made  had  been  "  liquid  " 
cultures,  such  as  were  invented  and  used  so  effectively  by 

1  Cohn's  Beitrage,  Bd.  II. 


54         RISE  AND   INFLUENCE   OF  BACTERIOLOGY 

Pasteur  in  his  establishment  of  the  germ  theory  of  fer- 
mentation and  the  germ  theory  of  disease. 

Koch  himself  had  used  only  liquid  cultures  in  his  great 
work  on  anthrax  published  in  1 876 ;  and  Lister,  Cohn  and 
a  host  of  others  who  studied  fermentation  and  diseases  be- 
tween 1869  and  1880  had  used  exclusively  liquid  cultures. 
In  all  these  cases,  however,  it  was  very  difficult  to  secure 
pure  cultures  because  of  the  easy  mingling  in  fluid  media 
(such  as  bouillon  or  other  fermentable  or  putrescible  liquids) 
of  various  kinds  of  microbes,  especially  if  the  latter,  as  often 
happened,  were  endowed  with  the  power  of  independent 
motion  and  could  swim  about.  It  was  only  by  working  on 
the  basis  of  chance,  and  inoculating  many  flaskfuls  by 
single  needlefuls,  that  pure  cultures  could  be  got.  This 
was  tedious,  uncertain,  unsatisfactory,  and  in  the  hands  of 
any  but  experts  almost  sure  to  lead  to  wrong  conclusions. 
Thus  it  happened  that  during  the  twenty  years  after  Pas- 
teur began  to  use  liquid  cultures,  progress  in  bacteriology 
was  slow  and  uncertain.  We  shall  now  see  why,  on  the 
contrary,  in  the  same  number  of  years  since  Koch  began 
his  use  of  "  solid  "  cultures,  bacteriology  has  advanced  by 
leaps  and  bounds. 

The  method  of  solid  culture  overcomes  the  worst  defects 
of  the  method  of  liquid  culture,  namely,  first,  the  promiscu- 
ous mingling  of  different  kinds  of  bacteria,  and  also,  sec- 
ond, the  time  and  labor  consequently  required  to  secure 
"  pure  "  cultures.  In  this  method  the  bouillon,  or  other 
liquid  medium  in  which  bacteria  will  thrive,  is  simply 
thickened  while  hot  with  gelatine  or  some  similar  substance 
such  as  Irish  moss  or  agar-agar,  so  that  when  cooled  the 
mass  becomes  a  soft,  moist  jelly,  capable  of  being  melted 
by  a  gentle  heat  and  solidified  at  the  temperature  of  an 
ordinary  room.  It  will  be  apparent  on  a  moment's  re- 
flection that  any  bacteria  or  similar  micro-organisms  pres- 
ent in  the  liquid  must  also  be  present  in  the  solid  mass, 
but  with  this  important  difference  of  condition,  viz.,  that 


DISCOVERY   OF  THE   TUBERCULOSIS  MICROBE       55 

whereas  in  the  liquid  they  float  or  swim  about  promiscu- 
ously, and  may  become  thoroughly  intermingled,  such  is 
not  the  case  in  the  solidified  mass,  in  which  each  is  brought 
to  rest  and  held  captive  at  some  small  distance  at  least  from 
every  other.  Moreover,  since  the  "  solid "  medium  con- 
tains as  abundant  nutrients  as  the  "  liquid,"  the  bacteria 
are  firmly  fixed  in  a  solid  which  is  at  once  their  prison  and 
their  food.  Accordingly,  they  continue  to  feed  and  multi- 
ply or  reproduce,  though  each  remains  fixed  at  or  very 
near  the  point  where  it  was  imprisoned.  After  a  day  or 
two,  as  a  result  of  continued  feeding  and  reproduction, 
microscopic  heaps  of  bacteria  are  formed,  which  finally 
become  visible  to  the  naked  eye  as  minute  dots,  and  when 
still  larger  are  known  as  "colonies."  If  the  parent  of 
the  colony  was,  as  is  usually  the  case,  a  single  isolated, 
individual  bacterium,  the  colony,  being  composed  solely 
of  the  descendants  of  this  germ,  will  be  a  "  pure  "  cul- 
ture, readily  and  immediately  supplying  the  material  for 
other  pure  cultures  of  the  same  species.  The  ease  and 
the  saving  of  time,  the  simplicity,  certainty,  and  accuracy 
of  the  method  are  obvious.  Its  superiority  to  the  method 
of  liquid  cultures  caused  its  immediate  adoption,  and  it 
speedily  led  to  the  establishment  of  bacteriology  as  a 
recognized  biological  science. 

Almost  immediately  the  new  science  began  to  yield 
wonderful  fruit,  for  in  the  next  year  (1882)  the  whole 
world  was  startled  at  the  announcement  by  Koch  of  his 
discovery  of  the  micro-organism  of  tuberculosis,  a  bacillus 
usually  found  in  the  sputum  of  patients  suffering  from 
pulmonary  consumption,  capable  of  cultivation  on  solid 
media  outside  the  human  body,  and  able  to  produce  the 
disease  when  inoculated  into  healthy  susceptible  animals, 
such  as  guinea-pigs.  This  announcement  caused  a  pro- 
found sensation  all  over  the  world ;  but  so  general  and  so 
conclusive  was  the  confirmatory  testimony  that,  in  a  sur- 
prisingly short  time,  it  was  accepted,  and  is  now  a  matter 


56         RISE  AND   INFLUENCE   OF   BACTERIOLOGY 

of  history.  The  next  year  (1883)  witnessed  the  discovery, 
also  by  Koch,  of  the  micro-organism  of  Asiatic  cholera, 
in  this  case  not  a  true  bacillus  or  rod,  but  a  curved  form ; 
hence  at  first  described  as  a  "  comma  "  bacillus  and  after- 
ward as  a  spirillum  or  vibrio.  One  year  more  (1884) 
yielded  the  rich  prizes  of  the  bacillus  of  diphtheria  and  that 
of  tetanus  (lock-jaw),  as  well  as  new  and  careful  studies 
by  Gaffky,  with  the  improved  methods,  upon  the  bacillus 
of  typhoid  fever  which  had  been  partially  worked  out 
previously  by  Eberth  and  Koch.  Very  much,  of  course, 
still  remained  to  be  done,  not  only  in  the  search  for  the 
germs  or  living  ferments  of  important  and  familiar  dis- 
eases, but  also  in  verifying  the  steps  already  taken ;  but 
it  is  no  exaggeration  to  say  that  within  five  years  from 
the  time  of  Koch's  introduction  of  the  method  of  solid 
cultures  the  new  science  of  bacteriology  had  achieved 
a  recognized  and  honorable  position.  Moreover,  the  zy- 
motic theory  of  infectious  disease  was  now  established,  and 
the  dreams  of  the  iatro-chemists  and  of  William  Farr  had 
come  true. 

We  shall  next  see  how  the  theory  of  infectious  disease 
as  due  to  living  ferments  has  been  gradually  further 
elaborated  into  a  theory  of  ferment-poisons,  or  in  other 
words  transformed  from  a  zymotic  into  a  zymotoxic  theory. 

§6. — How,  precisely ',  do  Living  Ferments  produce 
Disease  f 

A  little  reflection  will  show  that  there  are  several  ways 
in  which  invading  micro-organisms  might  conceivably  pro- 
duce disease  in  the  animal  body;  for  example,  (i)  by 
mere  physical  obstruction,  clogging  the  capillaries,  veins  and 
arteries,  and  interfering  mechanically  with  the  ordinary 
operation  of  the  vascular  and  other  mechanisms  ;  or  (2)  by 
chemical  interference,  such  as  (a)  theft  of  food  or  other 
chemical  compounds  needed  by  the  body,  or  (b}  by  the 


57 

generation  of  substances  harmful  to  the  body  and  there- 
fore to  be  reckoned  as  essentially  poisonous  or  "toxic." 
It  is  not  necessary  to  do  more  than  suggest  these  various 
possibilities  inasmuch  as  it  is  now  universally  agreed  that, 
while  other  influences  should  not  be  overlooked,  the  prin- 
cipal method  of  damage  lies  in  the  generation  of  toxic 
products  (toxins},  resulting  from  the  operation  of  living 
ferments  within  or  upon  the  organism.  This  will  be  more 
readily  understood  by  returning  for  a  moment  to  a  con- 
sideration of  the  alcoholic  fermentation.  In  the  case  of 
apple  juice  invaded  by  wild  yeasts,  it  is  indeed  true  that 
the  yeasts  multiply  enormously  and  enough  to  cause  a 
physical  change,  the  turbidity  of  the  liquid  ;  and  also  that 
sugar,  a  valuable  food  substance,  disappears  by  the  agency 
of  the  yeast.  But  the  most  striking  phenomenon,  and  one 
which  has  been  universally  recognized  as  such,  as  is 
proved  by  the  fact  that  this  fermentation  has  long  borne 
its  specific  name,  is,  that  a  new  and  toxic  substance, 
alcohol,  is  generated  during  the  fermentation.  In  a  word, 
just  as  yeast  may  be  considered  the  specific  germ  of  the 
alcoholic  fermentation,  alcohol  may  be  regarded  as  the 
toxic  substance  generated  by  it,  i.e.  alcohol  may  be  re- 
garded as  a  toxin  produced  by  yeast. 

We  must  hasten  to  remark,  however,  that  the  products 
of  fermentation  are  not  always  or  necessarily  poisonous 
either  in  character  or  quantity,  as  may  be  seen  in  the  case 
of  the  alcoholic  fermentation  just  cited  and  in  the  vinegar, 
lactic  and  similar  fermentations.  It  is  "however  interesting 
to  observe  that  the  character  of  the  substances  produced 
is  in  each  case  specific,  —  yeast  producing  alcohol,  the 
anthrax  germ  producing  anthrax  poison  or  toxin,  the  diph- 
theria bacillus  diphtherotoxin,  the  typhoid  fever  bacillus 
typhotoxin,  the  lock-jaw  bacillus  tetanotoxin,  and  so  on. 
But  if  this  be  so,  then  this  class  of  living  ferments  may 
easily  do  its  damage  by  means  of  its  products,  which  are 
harmful  to  the  body  just  as  poisons  are,  and  the  mystery 


58         RISE  AND   INFLUENCE   OF   BACTERIOLOGY 

of  an  infectious  disease  becomes  no  greater,  and  perhaps 
no  other,  than  a  mystery  of  toxicology,  such  as  exists,  for 
example,  in  the  case  of  poisoning  by  opium,  belladonna, 
strychnine,  and  similar  vegetable  poisons.  It  is  by  reason- 
ing of  this  sort,  based  upon  numerous  observations  and 
experiments,  that  the  modern  theory  of  infectious  disease 
has  reached  the  point  to  which  we  have  now  obviously 
come,  namely,  that  the  true  theory  of  infectious  disease 
is  not  merely  a  zymotic  or  ferment  theory,  but  rather  a 
zymotoxic  o\  ferment-poison  theory. 

It  is  plain  that  the  invading  micro-organisms  which  pro- 
duce disease  are  essentially  parasites,  and  that  the  germ 
theory  of  disease  is  a  theory  of  parasitism.  The  term 
"zymotoxic"  is  here  preferred  to  "parasitic"  simply  as 
being  more  definite  and  more  precise.  There  can  be  but 
little  doubt,  however,  that  the  growth  of  knowledge  of 
parasitism  materially  aided  the  acceptance  of  the  germ 
theory.  Favus  and  muscardine  have  already  been  cited 
as  early  examples,  and  the  discovery  of  trichinae  in  swine, 
and,  in  particular,  the  recognition  that  epidemics  may  be 
caused  by  these  microscopic  worms  doubtless  paved  the 
way  for  a  more  speedy  general  acceptance  of  a  parasitic 
or  germ  theory  of  infectious  disease.  To  this  aspect  of 
the  subject  we  shall  return  in  the  next  chapter. 

§  7.  —  Sefstns,  Ptomaines  and  Toxins 

It  has  long  been  recognized  that  spoiled  meat,  fish  and 
other  animal  foods  are  sometimes  dangerous  to  eat,  and 
the  popular  assumption  has  been  that  they  contained  some 
deadly  poisonous  substance.  As  early  as  1814,  according 
to  Woodhead,  Burrows  in  England  described  such  a  poi- 
sonous substance  in  putrefying  fish ;  while  Kerner,  in  1820, 
described  a  poisonous  alkaloid  which  resulted  apparently 
from  the  decomposition  of  albumen,  and  resembled  in  its 
physiological  action  a  substance  found  by  him  in  poison- 


BACTERIAL   OR   FERMENT  POISONS  59 

ous  sausages.  Kerner  compared  this  with  atropine,  the 
alkaloid  of  belladonna,  in  its  toxic  effects.  In  1856  Panum 
obtained  from  decomposing  animal  matter  a  characteristic 
product  soluble  in  water  or  alcohol  to  which  he  gave  the 
name  "  sepsin."  No  great  attention,  however,  was  paid 
to  these  substances  until  about  1870,  when  Selmi  drew 
general  attention  to  the  subject,  and  gave  to  the  so-called 
poisonous  alkaloids  the  name  "ptomaines,"  i.e.  "cadav- 
eric "  substances.  Nencki  and  also  Brieger  soon  obtained 
several  of  these  from  pure  cultivations  of  bacteria,  and 
since  that  time  it  has  been  generally  recognized  that  it  is 
easy  to  separate  from  substances  which  have  undergone 
fermentation  or  putrefaction  chemical  compounds  more  or 
less  characteristic  of  the  fermentation  or  putrefaction  in 
question.  When  these  are  poisonous,  they  are  often  de- 
scribed as  ptomaines ;  and  the  whole  group  is  popularly 
known  by  this  name,  though  it  is  obviously  unfit  for  the 
purpose.  Some  writers  have  undertaken  to  apply  the  word 
"  leucomaines  "  to  those  similarly  derived  but  harmless. 

A  more  recent  terminology  describes  the  poisonous 
products  of  fermentation  or  putrefaction  as  toxins,  and 
applies  no  name  to  the  non-poisonous  products.  As  we 
shall  soon  see,  the  ideas  advanced  in  this  paragraph  have 
received  widespread  attention,  and  must  be  regarded  as  of 
the  highest  importance  on  account  of  their  necessary  con- 
nection with  the  subjects  of  susceptibility  and  immunity 
upon  which  we  must  dwell  in  the  next  chapter. 

§  8.  —  Transformation  of  tJie  Zymotic  Theory  of  Infections 
Diseases  into  the  Zymotoxic  Theory  of  to-day.  Recapitu- 
lation 

Enough  has  now  been  said  to  make  it  clear  that  the 
modern  idea  of  an  infectious  disease  is  somewhat  more 
than  that  of  a  fermentation  or  a  case  of  parasitism.  It 
is  not  merely  that  the  body  of  the  patient  is  invaded  by 


60         RISE  AND   INFLUENCE   OF   BACTERIOLOGY 

germs ;  our  theory  goes  much  farther  than  this  and  shows 
us  the  germs  growing,  dividing  and  multiplying  in  the 
body  of  the  patient,  while  at  the  same  time  each  carries 
on  its  individual  metabolic  existence,  acting  upon  its  im- 
mediate environment,  drawing  to  itself  foods,  and  reacting 
by  setting  free  the  special  products  of  its  vital  activity. 
It  is  not  enough  to  suppose  that  the  micro-organisms  in 
question  mechanically  obstruct  or  physically  disturb  the 
delicate  machinery  of  the  living  organism  in  which  they 
multiply.  The  symptoms  of  infectious  disease  are  rather 
those  of  toxic  actions,  actual  poisonings  of  the  body, 
accompanied  by  chills,  fever,  delirium  and  other  symptoms 
of  a  profound  disturbance.  Moreover,  the  phases  of  infec- 
tious disease  —  the  slow  onset,  the  active  illness,  the  recov- 
ery and  the  subsequent  immunity  —  are  all  readily  explained 
upon  the  modern  theory  of  zymotoxic  action.  The  slow 
onset  is  apparently  due  to  the  limited  infection  and  the 
time  required  for  the  growth  of  the  germs.  The  gradual 
increase  of  severity  keeps  pace  with  their  multiplication 
and  activity.  The  height  of  the  disease  corresponds  to 
the  height  of  their  development.  Its  abatement  to  their 
decline.  The  subsequent  immunity  perhaps  to  the  habitu- 
ation  of  the  organism  to  their  poison.  The  subject  of 
immunity,  however,  is  by  no  means  well  understood.  It 
will  be  more  fully  considered  in  the  next  chapter. 

§  9.  —  Objections  to  the  Germ  Theory 

The  principal  objection  to  the  germ  theory  was  and  is 
that  already  referred  to  as  met  and  overcome  by  Koch, 
viz.,  that  germs  may  be  seemingly  the  consequence,  not 
the  cause,  of  disease.  Another  objection  is  that  in  certain 
diseases  the  most  careful  search  has  failed  thus  far  to  re- 
veal causative  micro-organisms.  The  answer  to  this  latter 
is  simply  that  in  the  absence  of  all  positive  evidence  of 
the  true  cause  of  disease  we  are  at  liberty  to  choose  the 


THE   ZYMOTOXIC  THEORY   OF   DISEASE  6l 

most  likely  working  hypothesis,  and  no  hypothesis  has  yet 
been  found  for  any  infectious  disease  more  reasonable  or 
more  probable  than  the  germ  theory. 

"  A  great  scientific  theory  has  never  been  accepted  with- 
out opposition.  The  theory  of  gravitation,  the  theory  of 
undulation,  the  theory  of  evolution,  the  dynamical  theory 
of  heat  —  all  had  to  push  their  way  through  conflict  to 
victory.  And  so  it  has  been  with  the  germ  theory  of  com- 
municable diseases."  * 

ITYNDALL,  Essay  on  "Louis  Pasteur,  His  Life  and  Labors." 


CHAPTER  IV 

SANITARY  ASPECTS  OF  THE  STRUGGLE  FOR  EXISTENCE. 
PARASITISM.  HEALTH  AND  DISEASE  IN  TERMS  OF  GEN- 
ERAL BIOLOGY.  VITAL  RESISTANCE,  SUSCEPTIBILITY  AND 
IMMUNITY 

"  Nothing  is  easier  than  to  admit  in  words  the  truth  of  the  universal 
struggle  for  life,  or  more  difficult  —  at  least  I  have  found  it  so  —  than 
constantly  to  bear  this  conclusion  in  mind." 

"  Let  it  also  be  borne  in  mind  how  infinitely  complex  and  close- 
fitting  are  the  mutual  relations  of  all  organic  beings  to  each  other  and 
to  their  physical  conditions  of  life." 

—  DARWIN.    "  The  Origin  of  Species." 

§  I.  —  Sanitary  Aspects  of  the  Struggle  for  Exist  erne 

IN  the  preceding  chapters  stress  has  been  laid  on  the 
potency  of  the  agents  of  disease  proceeding  from  the  en- 
vironment. This,  however,  is  only  one  aspect  of  the 
matter.  In  order  that  living  ferments  or  their  poisons 
shall  be  effective,  there  must  be  a  susceptible  subject  upon 
which  they  can  act.  Thus  it  comes  to  pass  that  in  any 
zymotic  disease  the  energy  and  virulence  of  the  attacking 
agents  are  virtually  pitted  against  the  resistance  of  the 
patient,  and  a  struggle  ensues  which  may  be,  and  often 
is,  on  one  side  or  on  both  sides  a  veritable  struggle  for 
existence.  In  this  case  the  struggle  is  between  organism 
and  organism,  between  man  and  microbe.  In  "The 
Origin  of  Species "  Darwin,  in  dealing  with  the  struggle 
for  existence,  dwells  chiefly  upon  similar  struggles  of 
living  things  one  with  another,  and  it  is  this  aspect  of 
the  subject  which  is  still  most  often  emphasized.  For  the 

62 


THE  PARABLE  OF  THE  SOWER         63 

hygienist,  however,  the  struggle  for  existence  means  not 
only  competition  and  battle  and  their  consequences,  not 
only  the  struggle  of  organism  with  organism,  but  also 
the  broader  struggle  of  the  individuals  with  their  whole 
environment.  In  the  familiar  parable  of  the  sower  we 
have  a  vivid  picture  of  such  a  struggle  for  existence  in 
the  case  of  certain  seeds :  — 

"  Behold,  a  sower  went  forth  to  sow ;  And  when  he 
sowed,  some  seeds  fell  by  the  wayside,  and  the  fowls 
came  and  devoured  them  up :  Some  fell  upon  stony  places 
where  they  had  not  much  earth ;  and  forthwith  they  sprung 
up,  because  they  had  no  deepness  of  earth :  And  when 
the  sun  was  up,  they  were  scorched ;  and  because  they 
had  no  root,  they  withered  away.  And  some  fell  among 
thorns ;  and  the  thorns  sprung  up,  and  choked  them  :  But 
others  fell  into  good  ground,  and  brought  forth  fruit." 

In  this  parable  both  aspects  of  the  struggle  for  exist- 
ence are  dwelt  upon :  first  the  struggle  of  organism  with 
organism,  namely,  of  seeds  with  birds  and  with  thorns ; 
and,  second,  of  organism  with  lifeless  environment,  namely, 
with  stony  places,  scorching  sun  and  good  earth.  A 
similar  breadth  of  view  is  required  for  the  student  of  sani- 
tary science  who  seeks  to  gain  a  philosophic  knowledge 
of  the  nature  of  disease;  for  disease  may  be  the  conse- 
quence not  merely  of  organism  struggling  with  organism, 
but  also  of  organism  struggling  with  lifeless  environment. 
It  is  perhaps  most  often  the  result  of  both  hostile  organism 
and  unfavorable  lifeless  environment  acting  together  upon 
the  human  mechanism.  Of  the  struggle  of  organism 
with  organism  parasitism  affords  a  familiar  and  instruc- 
tive example. 

§  2. — Parasitism  and  Infectious  Disease 

Some  recognition  of  what  is  now  known  as  parasitism 
must  have  occurred  very  early  in  the  history  of  the  human 


64     THE  "STRUGGLE   FOR  EXISTENCE"  AND  DISEASE 

race.  It  is  exemplified,  for  example,  in  the  case  of  the 
gourd  which  grew  up  and  sheltered  Jonah  while  he  impa- 
tiently waited  for  the  destruction  of  Nineveh,  inasmuch 
as  a  worm  was  sent  in  the  night  to  feed  upon  and  destroy 
the  gourd  ;  and  it  is  said  that  Pliny  was  familiar  with 
the  parasitism  of  the  mistletoe.  The  word  "  parasite," 
however,  arose  in  a  different  connection  and  was  only 
recently  applied  to  plants  and  the  lower  animals,  having 
been  apparently  first  used  for  a  person  who  unbidden  eats 
beside,  or  at  the  table  of,  another,  and  therefore,  of  course, 
lives  at  his  expense.  A  few  cases  of  parasitism,  such  as 
that  of  the  mistletoe,  were  recognized  very  early  because 
they  were  so  conspicuous  that  they  could  not  readily  be 
overlooked.  The  well-known  lines  of  Swift1  testify  unmis- 
takably to  a  recognition  of  the  same  phenomenon.  For 
the  most  part,  however,  parasitism  remained  comparatively 
unrecognized  until  the  introduction  of  the  compound  micro- 
scope revealed  its  almost  universal  prevalence. 

Parasitism  is  now  known  to  be  one  of  the  commonest 
features  of  the  struggle  for  existence,  and  it  is  not  neces- 
sarily, as  it  is  often  supposed  to  be,  an  abnormal  and 
strange  development — at  least  in  its  beginnings.  If,  in 
the  search  for  food,  a  plant  or  animal  happens  to  come  in 
contact  with  and  feed  upon  another,  it  may  easily  result 
that  it  shall  gain  great  profit  thereby,  though  if  this  habit 
becomes  so  extended  as  to  lead  to  the  destruction  of  the 
host,  the  parasite  itself  may  also  perish.  It  is  not  difficult 
to  suppose  that  parasitism  may  have  arisen  from  sapro- 

1  "  So,  naturalists  observe,  a  flea 

Has  smaller  fleas  that  on  him  prey; 
And  these  have  smaller  still  to  bite  'em. 
And  so  proceed  ad infinitum" 
Of  which  a  more  popular,  alliterative  and  generalized  version  is,  — 

"  Big  bugs  have  little  bugs 
Upon  their  backs  to  bite  'em; 
And  little  bugs  have  lesser  bugs, 
And  so  ad  infinitum." 


MICROBES   SOMETIMES   PARASITES  65 

phytism,  in  which  plants  or  animals  feeding  upon  dead  or 
waste  organic  matters  happened  to  become  attached  to 
living  plants  or  animals,  and  it  is  easy  to  see  how,  under 
these  circumstances,  great  advantage  might  accrue  to  the 
saprophyte.  It  is  even  possible  to  imagine  how  the  ranks 
of  parasites,  thinned  by  the  destruction  of  their  hosts,  or 
otherwise,  might  continually  be  recruited  from  among  the 
saprophytes. 

The  somewhat  extended  discussion  of  the  germ  theory 
of  fermentation  and  disease  in  the  previous  chapter  should 
not  lead  the  reader  to  overlook  the  fact  that  many  of  the 
micro-organisms  which  are  the  prime  movers  of  fermenta- 
tion and  infectious  disease  must  from  another  point  of  view 
often  be  regarded  as  parasites.  The  parasitic  fungi  have 
long  been  known  in  special  cases  to  penetrate  the  tissues  of 
their  host  precisely  as  microbes  may  "invade"  the  animal 
body.  It  has  also  been  known  that  in  doing  this  some 
solvent  reagent  was  secreted  by  the  fungus,  and  experi- 
ments have  shown  that  it  is  possible  to  separate  from  par- 
ticular fungi  substances  which  will  corrode  and  destroy 
vegetable  tissues.  It  thus  appears  that  a  close  analogy  is 
discoverable  between  the  toxins  or  poisonous  products  of 
disease  germs  and  these  solvent  reagents  or  tissue-poisons. 

It  is  customary  to  speak  of  the  infectious  diseases  as 
essentially  parasitic  in  their  character,  the  disease  germs 
being  the  parasites,  and  the  organisms  affected  their  hosts. 
This  point  of  view  is  not  only  common,  but  exceedingly 
useful,  for  it  places  these  diseases  in  the  same  category 
with  certain  well-known  phenomena  of  parasitism  (or  sapro- 
phytism),  and  makes  them  thereby  the  more  readily  com- 
prehensible. The  sanitarian  in  particular  has  reason  to 
value  this  interpretation  of  infectious  disease  inasmuch  as 
prevention  of  parasitism  is,  in  theory  at  least,  a  compara- 
tively simple  matter,  namely,  the  destruction  of  the  parasites 
in  question  and  their  control  in  the  environment.  When  it 
comes,  however,  to  an  examination  of  the  precise  nature  of 

F 


66     THE  "STRUGGLE  FOR   EXISTENCE"  AND   DISEASE 

the  parasitism  involved  in  infectious  disease,  we  shall  find 
it  often  necessary  to  regard  the  germs  as  parasites  produc- 
ing chemical  change  and  doing  damage  by  the  chemical 
changes  which  they  effect,  or  the  chemical  bodies  which 
they  produce,  rather  than  by  the  theft  of  food  substances 
which  is  the  more  ordinary  characteristic  of  parasitism. 

The  germ  theory  is  sometimes  thus  described  as  the 
parasitic  theory  of  disease,  and  has  also  been  called  the 
"  particulate "  theory  because  the  micro-organisms  con- 
cerned are  obviously  material  particles.  This  latter  desig- 
nation is  of  value  chiefly  as  emphasizing  the  reality  of 
the  materies  morbi,  or  the  fact  that  the  causes  of  infectious 
disease  are  material  particles  and  not  merely  immaterial 
conditions  such  as  dynamical  derangements  of  spiritual 
vital  principles.  The  reader  will  be  the  better  prepared 
to  recognize  the  validity  of  the  former  term  —  the  parasitic 
theory — if  he  will  remember  that  just  before  the  germ 
theory  had  taken  definite  shape  two  diseases,  namely, 
muscardine  in  silkworms  and  favus  or  honeycomb  of  the 
human  scalp,  had  already  been  proved  to  be  due  to  para- 
sitic fungi  (see  Chapter  II,  p.  32).  Powerful  support  for 
a  parasitic  theory  of  disease  had  also  been  accumulating 
during  the  time  of  the  growth  of  the  germ  theory  of  fer- 
mentation and  disease,  especially  in  connection  with  a 
terrible  disease  of  man  hitherto  unsuspected,  but  by  that 
time  definitely  known,  namely,  the  disease  caused  by 
the  parasite  called  the  pork-worm  (Trichina  spiralis}  and 
known  as  trichinosis.  This  disease  is  of  special  interest 
to  sanitarians,  inasmuch  as  the  parasites  which  unquestion- 
ably produce  it,  while  very  minute  are  still  scarcely  to  be 
called  micro-organisms,  and  yet  are  so  small  that  for  a  long 
time  they  escaped  the  detection  which  tapeworms,  stomach- 
worms,  etc.,  readily  encountered.  They  thus  form  an 
interesting  connecting  link  between  the  invisible  micro- 
organisms and  the  coarsely  visible  tapeworms,  etc.,  and  the 
smaller  fungi.  (Cf.  pp.  293,  296.) 


THE   "PARASITIC"  THEORY   OF   DISEASE  67 

The  whole  matter  may  perhaps  be  summed  up  as  fol- 
lows :  from  the  widest  point  of  view  infectious  diseases 
in  common  with  all  others  are  important  and  complicated 
phenomena  in  the  universal  struggle  of  organisms  for 
existence.  From  a  somewhat  narrower  point  of  view  they 
are  often  to  be  regarded  as  cases  of  parasitism,  the  disease 
germ  being  the  parasite  and  the  organism  affected  being 
its  host.  From  a  still  narrower  point  of  view,  and  examin- 
ing the  details  of  the  struggle,  the  process  appears  to  be 
essentially  "  toxic,"  the  host  being  damaged  by  the  para- 
site (or  saprophyte)  not  so  much  by  theft  of  material  as  by 
the  products  of  its  metabolic  activity,  namely,  by  chemical 
poisons  known  as  "  toxins." 

§  3.  —  The  Lifeless  Environment  and  Disease 

Any  extended  treatment  of  this  subject  would  be  beyond 
the  province  of  a  work  like  this,  since  such  a  discussion 
belongs  rather  to  hygiene  than  to  sanitary  science.  Nev- 
ertheless, the  student  of  sanitary  science  cannot  neglect 
the  influence  of  the  lifeless  environment  as  a  powerful 
factor  in  the  causation  and  modification  of  infectious  disease, 
even  when  it  is  not  the  principal  factor.  In  such  disease, 
for  example,  the  time,  the  occurrence,  the  duration  and 
even  the  energy  of  the  attack,  may  be  profoundly  influ- 
enced by  external  environmental  conditions  such  as  season, 
temperature,  dryness  or  light.  We  may,  therefore,  with 
advantage,  consider  somewhat  carefully  the  relations  be- 
tween organisms  and  their  environments,  whether  living 
or  lifeless,  before  passing  on  to  the  more  recondite  sub- 
jects of  susceptibility,  vital  resistance  and  immunity. 

In  addition  to  a  comprehension  of  the  fact  that  the  living 
organism  is  essentially  a  delicate  physical  mechanism,  the 
student  requires  an  adequate  knowledge  of  what  is  meant 
by  the  terms  "  organism  "  and  "  environment,"  and  with  this 
a  recognition  of  the  significance  of  the  actions,  reactions 


68     THE  "STRUGGLE   FOR  EXISTENCE"  AND   DISEASE 

and  interactions  which  necessarily  go  on  between  organ- 
isms and  their  environments. 

In  the  language  of  biology  an  organism  is  a  limited  mass 
of  living  matter  occupying  a  definite  position  in  space  and 
time.  It  is  bounded  on  all  sides  by  material  substances,  — 
earth,  air,  water,  etc.,  —  by  which  it  is  acted  upon,  and  upon 
which  it  acts  in  return,  and,  on  the  whole,  these  actions  and 
reactions  are  equal,  though  in  opposite  directions.  Those 
portions  of  the  material  universe  which  thus  act  upon  the 
organism  are  called  its  "environment,"  and  a  little  reflec- 
tion will  show  that  while  it  is  the  nearer  portions  which  are 
most  closely  concerned  and  are,  therefore,  the  most  con- 
spicuous parts  of  "  the  environment,"  no  part,  in  theory  at 
least,  is  so  remote  as  to  have  no  influence.  The  whole 
material  universe  may  be  —  must  be — divided  for  any  liv- 
ing thing  into  two  parts,  namely,  that  thing  and  its  envi- 
ronment :  the  individual  on  the  one  hand,  and  the  rest  of 
the  universe  on  the  other,  —  very  much  as  the  ancient  and 
mediaeval  philosophers  regarded  man  on  the  one  hand  as 
"  microcosm  "  and  the  rest  of  the  universe  as  "  macrocosm." 
Biology  teaches  that  if  we  would  comprehend  the  doings  of 
living  things  we  must  begin  by  taking  this  point  of  view. 
Viewed  from  this  standpoint  mankind  becomes  a  host  of 
masses  of  matter  each  bounded  by  the  rest  of  the  material 
universe,  with  which  it  must  deal  so  long  as  it  continues  to 
live,  and  to  which,  no  matter  how  prolonged  the  struggle,  it 
must  finally  surrender.  From  the  environment  each  must 
derive  whatever  of  matter  and  energy  it  gains,  and  to  it 
it  must  return  whatever  it  loses.  It  may  be  profoundly 
affected  by  heat  or  cold,  by  lightning  or  earthquake,  by  fire 
or  tempest ;  and  it  may,  on  its  part,  react  upon  its  environ- 
ment and  displace  the  air  by  buildings  or  balloons,  the  sea 
by  ships,  the  earth  by  mines  or  tunnels,  or  fire  by  incom- 
bustible substances.  Every  tree  that  lifts  its  branches 
into  the  aerial  ocean  reacts  upon  the  atmosphere  and,  like 
every  animal  that  burrows  into  the  earth  or  builds  its 


ORGANISMS   AND   ENVIRONMENTS  69 

house  or  its  nest  in  the  air,  reacts  upon  its  environment 
The  encroachments  of  the  sea  may  be  resisted  or  overcome 
by  dikes,  of  the  wind  by  shelters,  of  the  sunshine  by 
shade.  Everywhere  in  nature  —  and  in  man  as  a  part  of 
nature  —  we  find  actions  and  reactions  incessantly  going 
on,  and  these  in  the  long  run  consist  essentially  of  ex- 
changes of  matter  and  of  energy  or  of  both,  between 
masses  of  matter  and  their  environments. 

§  4.  —  Health  and  Disease  in  Terms  of  General  Biology 

Life  has  been  defined  as  "  the  continuous  adjustment  of 
internal  to  external  relations,"  and  health  might  be  de- 
fined on  these  terms  as  the  normal  state  and  performance 
of  this  adjustment.  Disease  would  then  be  some  serious 
disturbance  or  grave  departure  from  this  normal  state  or 
performance,  and  might  conceivably  be  due  to  (i)  a 
failure  of  the  intrinsic  powers  of  adjustment ;  or  (2)  some 
external  condition  so  severe  or  unusual  that  the  usual 
adjustment  was  impossible ;  or  (3)  to  a  combination  of 
these  factors.  From  what  was  said  in  the  first  chapter 
(p.  12)  it  is  clear  that  a  failure  of  the  mechanism  itself  to 
do  its  part,  a  failure  of  the  intrinsic  powers,  such,  for 
example,  as  old  age  effects,  produces  a  constitutional  dis- 
turbance or  disease ;  while  external  conditions,  so  hard  or 
so  unusual  as  to  be  met  with  difficulty  or  perhaps  not  at 
all,  may  well  give  rise  to  a  disturbance  or  disease  essen- 
tially environmental  in  its  origin ;  and  the  combined 
effect  of  imperfect  mechanism  or  imperfect  internal  ad- 
justment with  external  relations  difficult  to  deal  with 
might  lead  to  diseases  seemingly  environmental,  but  really 
no  less  truly  constitutional  in  origin.  A  very  little  reflec- 
tion will  show  that  to  avoid  disease  and  to  forestall  its 
effects  there  are  required:  (i)  Mechanisms  as  capable  as 
possible  of  adjustment  to  external  relations,  unfavorable 
as  well  as  favorable.  (2)  Environments  (external  rela- 


70     THE  « STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

tions)  to  which  the  mechanism  may  readily  adjust  itself, 
or  making  as  small  demands  as  possible  upon  its  powers 
of  adjustment. 

Of  these  two  factors  the  former  is  on  the  whole  far  the 
less  under  our  control  at  present.  The  mechanism  may  in- 
deed, as  a  rule,  be  strengthened  by  good  air,  good  food,  rest 
and  other  favorable  conditions  ;  it  may  be  weakened  by  bad 
air,  bad  food,  fatigue  and  other  unfavorable  conditions ;  so 
that  it  shall  adjust  more,  or  less,  successfully  its  internal  to 
any  external  relations.  But  while  so  much  is  unquestion- 
ably true,  and  while  efforts  looking  in  this  direction  lie  at  the 
basis  of  all  sound  hygiene  and  constitute  one  of  its  proper 
functions,  it  is  still  true  that  the  external  relations  to  which 
the  internal  relations  of  the  mechanisms  must  be  adjusted, 
are  much  more  largely  under  our  control.  In  other  words, 
it  is  to  a  great  extent  within  our  power  (in  theory  at 
least)  to  provide  environments  or  external  relations  to 
which  almost  any  living  mechanism  should  be  able  to 
adjust  its  internal  relations ;  or,  conversely,  an  environ- 
ment so  unfavorable  that  few  if  any  could  possibly  be 
able  to  adjust  themselves  to  it.1 


§  5.  —  Three  Principal  Sanitary  Conditions  or  States  of 

Relation 

In  actual  life  all  these  various  conditions  are  readily 
observed.  We  find  some  persons  so  robust  —  that  is  to 
say,  with  mechanisms  so  capable  of  adjustment  to  external 

1  "The  man  who  lives  to  the  age  of  a  hundred  years  and  who,  during  that 
time,  suffers  no  pain,  and  is  continually  able  to  make  use  of  the  powers  pecul- 
iar to  his  age,  would  by  universal  testimony  be  regarded  as  an  example  of 
health  ;  yet  even  the  life  of  such  an  one  would  not  always  be  at  its  best  ;  and 
health,  like  every  other  such  name,  is  to  be  used  in  a  relative  sense.  Into  the 
life  of  the  healthiest  man  disorders  must  frequently  enter.  Absolute  health 
is  an  ideal  conception,  as  the  line  of  the  mathematician,  the  ether  of  the 
physicist,  and  the  atom  of  the  chemist."  — T.  C.  ALLBUTT,  "  System  of  Medi- 
cine," I,  xxil 


SANITARY  PARADOXES  71 

relations  of  whatever  kind  —  that  nothing  seems  to  daunt 
them.  They  work  hard,  eat  poor  food,  live  in  bad  air 
and  seemingly  disobey  all  the  rules  of  hygienic  living,  and 
yet  possess  apparently  perfect  health.  Conversely,  others 
surrounded  by  every  sanitary  contrivance,  well  fed,  well 
housed  and  tenderly  cared  for,  sicken  and  die  in  an  envi- 
ronment apparently  the  most  absolutely  favorable.  And 
finally,  in  the  same  community,  are  many  who  thrive  as 
long  as  their  external  relations  are  good  and  easily  dealt 
with  ("favorable"),  but  who  suffer  just  as  soon  as  these 
become  difficult  to  deal  with  ("  unfavorable  "). 

Furthermore,  these  groups  are  by  no  means  fixed  and 
invariable,  but  rather  constantly  subject  to  change  both  as 
to  membership  and  mass.  A  period  of  unusual  environ- 
mental severity  of  climate,  temperature,  infection,  finan- 
cial or  political  buoyancy  or  depression,  may  promote  or 
reduce  from  one  rank  to  another,  with  the  consequence  not 
only  of  numerous  changes  in  actual  sanitary  conditions  in 
individuals,  but  even  extensive  improvement  or  deteriora- 
tion in  the  average  public  health  of  a  community.  Of 
this  a  good  example  is  some  effective  change  in  external 
relations,  such  as  a  financial  panic,  causing  anxiety,  loss  of 
employment,  increased  exposure,  poorer  feeding,  loss  of 
sleep,  etc.,  but  perhaps  the  best  example  is  one  in  which  a 
novel  and  direct  action  proceeds  from  the  environment, 
unknown,  it  may  be,  until  its  work  is  done.  Such  a  pro- 
found change  in  the  external  relations  of  an  entire  com- 
munity occurs  when  some  epidemic,  unsuspected,  falls 
upon  an  entire  city  or  town.  There  are  on  record  many 
cases  of  this  kind,  some  of  which  are  described  in  the 
eighth  chapter.  If,  for  example,  a  public  water  supply 
becomes  contaminated  with  the  germs  of  an  infectious 
disease  such  as  typhoid  fever,  the  general  standard  of 
health  in  the  community  using  it  will  be  lowered,  the  weak, 
as  a  group,  will,  on  the  whole  become  weaker,  the  strong, 
less  strong,  and  some  of  each  group  will  perish  altogether 


72     THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

who   would   have  lived   longer  if   the   infection   had  not 
reached  them. 

The  explanation  of  these  three  great  groups  —  which 
we  may  call  "the  robust"  or  "the  strong,"  "the  well  but 
not  strong,"  and  "the  feeble"  or  "weak"  -is  simply 
that  there  are  actually  corresponding  groups  of  organisms, 
or  mechanisms,  in  every  community.  The  "  strong  "  are 
those  endowed  by  nature,  by  inheritance,  or  it  may  be  to 
some  extent  by  training,  with  superior  vital  machinery. 
"  The  well  but  not  strong "  are  similarly  provided  with 
machinery  either  poorer  in  quality  or  less  successfully  put 
together,  while  the  "  weak  "  or  "  feeble  "  are  those  hav- 
ing vital  mechanisms  so  delicate  in  fibre  or  adjustment  as 
to  be  always  in  need  of  attention  or  repair,  even  under 
ordinarily  good  conditions.  It  will  be  observed  that  no 
place  is  here  left  for  those  organisms  which  are  altogether 
wanting  in  the  power  of  "continuous  adjustment  of  inter- 
nal to  external  relations."  Such  are  those  that  perish,  — 
some,  before  they  are  born ;  some,  vainly  trying  at  birth  to 
catch  the  first  breath  of  life  in  order  themselves  to  effect 
an  oxygenation  of  their  blood,  hitherto  provided  for  from 
the  mother,  from  the  novel  atmospheric  ocean  in  which  if 
anywhere  they  must  henceforward  live;  some,  later,  in 
that  struggle  for  existence  which  compels  them  to  deal 
with  bad  food,  or  exposure,  or  infection,  or  with  sorrow 
or  shame.  Few,  comparatively,  are  able  to  adjust  their 
internal  to  their  external  relations  so  successfully  as  to 
reach  the  familiar  threescore  years  arid  ten ;  fewer  still 
the  fourscore  years;  and  we  have  the  authority  of  the 
psalmist  that  in  the  latter  case  it  is  only  "by  reason  of 
strength "  that  the  goal  is  reached :  favorable  environ- 
ments —  favorable  external  relations  —  alone  are  not  suffi- 
cient. The  power  of  adjustment  of  internal  relations  is 
equally  indispensable. 


THE   STRONG  AND  THE  WEAK  73 

§  6.  —  Practical  Importance  of  these  Considerations 

The  practical  importance  of  these  considerations  is  im- 
mense. Any  one  who  deals  chiefly  with  those  more  violent 
changes  in  the  environment  which  produce  great  destruc- 
tion in  a  relatively  short  space  of  time  is  tempted  to  mini- 
mize the  importance  of  forces  acting  more  slowly  over 
longer  periods.  The  epidemiologist,  for  example,  after 
witnessing  the  conspicuous  effects  of  an  outbreak  of  dis- 
ease affecting  a  whole  community  through  impure  food  or 
drink,  is  strongly  tempted  to  overlook  the  relatively  remote 
effects  of  ordinary  filth  or  foul  air.  And  these  are  in  fact 
far  less  striking,  even  when  discoverable  at  all.  But  yet 
there  is  reason  to  believe  that  even  quantitatively  con- 
sidered they  may  do  quite  as  much  or  even  far  more  harm 
in  the  long  run,  for  the  great  epidemics  come  seldom, 
affect  a  small  number  only,  and  pass  quickly  ;  while  filth 
and  bad  air  act  unfavorably  upon  a  much  larger  number 
for  a  much  longer  time,  keeping  them  frequently  and  per- 
haps constantly  weakened,  and  enhancing  always  their 
susceptibility  to  specific  disorders. 

Nor  must  we  allow  ourselves  to  be  deceived  by  appear- 
ances. It  is  true  that  abounding  health  is  often  exhibited 
by  those  dwelling  in  most  unwholesome  places,  and  that 
many  who  never  wash  outlive  many  who  do.  But  this  does 
not  mean  that  sanitary  dwellings  are  superfluous,  or  that 
bathing  is  a  waste  of  time.  Nothing  is  plainer  in  sanitary 
science,  as  in  human  experience,  than  that  "  Cleanliness  is 
next  to  Godliness,"  and  that  on  the  whole  the  first  external 
condition  of  health  is  cleanliness.  On  looking  closely  we 
shall  find  that  the  cases  observed  are  exceptional,  or  that 
the  persons  in  question  are  the  strong  survivors  of  many 
now  dead  among  whom  they  represent  the  survival  of  the 
fittest ;  or  that  they  have  really  bathed  in  their  own  sweat, 
thus  shedding  off  the  outer  skin  and  with  it  much  dirt  and 
many  micro-organisms ;  or  finally,  that  although  the  sur- 


74    THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

viving  younger  members  of  the  family  may  seem  hale  and 
hearty,  the  elders,  while  still  young  in  years,  show  the 
effects  of  the  struggle  for  existence  and  often  break  down 
or  succumb  to  disease  before  their  natural  time. 

Darwin  somewhere  refers,  more  in  sorrow  than  in  anger, 
to  those  persons  who  have  failed  to  understand  him  because 
they  were  utterly  unable  to  appreciate  the  cumulative  ef- 
fects of  small  changes  acting  over  long  periods  of  time. 
The  sanitarian  needs  constantly  to  be  warned  against  the 
neglect  of  small  and  seemingly  insignificant  factors  of 
disease  in  the  form  of  unfavorable  conditions  which  by 
their  prolonged  action  and  cumulative  effects  may  produce 
great  results. 

§  7.  —  Vital  Resistance  and  Susceptibility 

The  reader  is  now  in  a  position  to  understand  in  its 
general  aspects  the  term  "vital  resistance."  In  the  last 
analysis  this  expression  is  used  to  describe  that  condition 
of  the  normal  body,  plant  or  animal,  in  which  it  is  able  to 
cope  more  or  less  successfully  with  unfavorable  influences 
acting  upon  it  from  without,  i.e.  from  the  environment. 
There  is,  however,  no  quantitative  measure  of  vital  resist- 
ance; but  when  it  is  regarded  as  small  or  altogether 
wanting,  the  term  is  no  longer  used,  and  the  organism  is 
said  to  be  not  vitally  resistant,  but  "susceptible"  or  "vul- 
nerable "  to  disease.  At  the  other  extreme,  when  the  vital 
resistance  is  complete,  especially  in  regard  to  parasites, 
poisons,  etc.,  the  organism  is  said  to  be  "  immune,"  as  are, 
for  example,  the  arsenic  eaters  of  Styria  against  ordinarily 
lethal  doses  of  arsenic,  and  as  are  certain  trees  to  certain 
parasites.  Enough  has  perhaps  already  been  said  in  the 
previous  section  in  regard  to  susceptibility  of  different  de- 
grees, but  immunity  is  a  matter  of  so  much  practical  impor- 
tance that  it  will  be  necessary  to  consider  it  much  more 
carefully  in  the  following  sections. 


CUMULATIVE  EFFECTS  OF  UNSANITARY  FACTORS     75 

It  has  been  suggested  by  Professor  Theobald  Smith  that 
the  mutual  relations  of  vital  resistance  and  infectious  dis- 
ease may  be  the  more  clearly  appreciated  by  expressing 

M 

them  in  the  form  of  an  equation,  namely,  D  =  — ,  in  which 

R 

D  represents  the  disease,  M  the  micro-organism  and  R 
the  vital  resistance  of  the  organism  attacked.  Obviously, 
D  will  vary  according  to  the  relative  values  of  M  and  R. 
It  is  even  possible  to  carry  this  idea  somewhat  farther  and 

to  write  the  equation  D  =  — - — ,  N  representing  the  num- 

R 

ber  of  micro-organisms  and  V  their  virulence ;  for  there  is 
good  reason  to  suppose  that  the  intensity  of  the  disease  de- 
pends on  these  factors  as  well  as,  though  less  than,  on  M, 
the  specific  character  of  the  micro-organism  involved.  We 
are  unable  at  present  to  resolve  R  into  any  component 
elements  or  even  to  picture  to  ourselves,  except  in  the 
most  general  way,  its  origin  or  mechanics.  We  may,  it  is 
true,  safely  consider  that  it  is  bound  up  with  chemical  and 
physical  processes  which  result  in  favorable  chemical  and 
physical  conditions ;  but  concerning  these  processes,  and  to 
a  great  extent  these  conditions,  we  are  at  present  almost 
completely  ignorant.  (Cf.  pp.  98,  218.) 

§  8. — Immunity 

Examples  of  comparative  immunity  to  infectious  disease 
are  familiar  in  the  cases  of  all  robust  and  healthy  persons. 
Precisely  what  the  basis  of  this  immunity  may  be  it  would 
be  difficult  to  say,  but  it  is  not  inconceivable  that  in  an 
organism  which  is  a  practically  perfect  mechanism  the  con- 
ditions should  be  such  as  to  ward  off  effectually  all  micro- 
organisms, either  by  mechanical  or  physiological  defences. 
Among  the  former  would  be  healthy  and  vigorous  skins 
and  epithelia,  which  the  invaders  should  find  it  impossible 
to  penetrate;  among  the  latter,  juices  of  the  body  of  such 
composition  as  to  be  essentially  toxic  or  destructive  for 


76     THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

invading  microbes.  There  is  good  reason  to  believe  that 
such  conditions  are,  in  fact,  some  at  least  of  those  which 
constitute  the  robustly  healthy  organism  immune  to  all 
ordinary  infectious  diseases. 

It  has  long  been  the  ambition  of  dreamers  to  find  some 
substance  which  should  not  only  ward  off  the  attacks  of 
infectious  disease  but  also  interfere  with  the  ordinary 
course  of  Nature,  and  postpone  for  a  longer  or  shorter 
time  the  arrival  of  old  age.  Various  elixirs  of  life  have 
been  put  forward  by  enthusiasts,  especially  with  a  view  to 
the  latter  result,  and  it  must  be  allowed  that,  improbable 
as  it  is  that  this  end  will  ever  be  achieved,  it  is  not  per- 
haps theoretically  inconceivable.  It  is  plain,  however,  that 
inasmuch  as  there  frequently  exists  already  a  remarkable 
natural  immunity  to  certain  infectious  diseases,  the^problem 
of  artificial  immunity  to  disease  is  one  much  easier;  and 
when  we  learn,  as  is  the  fact,  that  such  immunity  has 
actually  been  produced  in  the  case  of  some  diseases,  we 
may  confidently  expect  that  it  shall  be  eventually  brought 
about  in  the  case  of  other  diseases  also. 


§  9.  —  Immunity  to  Small-pox.     Inoculation 

The  development  of  our  knowledge  in  this  direction  is 
interesting  and  instructive.  The  first  systematic  steps 
toward  securing  artificial  immunity  from  disease  appear  to 
have  been  taken  in  the  case  of  small-pox.  In  the  early 
part  of  the  eighteenth  century,  Lady  Mary  Wortley  Mon- 
tagu, the  wife  of  the  British  ambassador  at  Constantinople, 
the  daughter  of  a  duke  and  the  granddaughter  of  an  earl, 
and  a  woman  of  rare  gifts,  in  interesting  letters  sent  from 
Constantinople  to  friends  at  home  pointed  out  that  the 
Turks,  in  pursuance  of  a  custom  apparently  derived  from 
the  East,  were  in  the  habit  of  "  inoculating  "  against  small- 
pox. Lady  Montagu  wrote  from  Adrianople  in  1717: 
"  Every  year  thousands  undergo  this  operation,  and  the 


NATURAL    VS.  ARTIFICIAL   IMMUNITY  77 

French  ambassador  says  pleasantly  that  they  take  the 
small-pox  here  by  way  of  diversion,  as  they  take  the  waters 
in  other  countries.  There  is  no  example  of  any  one  hav- 
ing died  of  it,  and  you  may  believe  I  am  satisfied  of  the 
safety  of  their  experiment  since  I  intend  to  try  it  on  my 
dear  little  son."  Largely  as  a  result  of  this  correspondence 
the  practice  of  inoculation  was  introduced  into  England, 
and  thence  carried  to  America.  In  both  countries  it  be- 
came widely  extended,  and  lasted  for  many  years.  It  is 
said  that  the  first  person  inoculated  in  England  was  Lady 
Montagu's  daughter.  George  I  and  several  members  of 
his  family  were  soon  after  inoculated,  as  were  also  many 
less  noted  persons,  and  the  practice  gradually  became 
common. 

In  the  process  of  inoculation  for  small-pox,  some  "  mat- 
ter" derived  from  a  pustule  of  a  small-pox  patient  was 
introduced  under  the  skin  of  a  healthy  person  who  elected 
to  suffer  from  the  disease  while  well,  and  knowingly, 
rather  than  to  run  the  risk  of  "  taking  "  it  when  less  well, 
unknowingly.  The  process  was  much^ie  same  as  that 
employed  in  vaccination  except  that  the  'Matter  "  used  was 
derived  directly  from  the  pustules  of  a  ^«ll-pox  patient, 
and  was  not  "  vaccine  "  matter,  i.e.  was  not  derived  either 
directly  or  indirectly  from  the  cow..  Inoculation  had  a 
very  extended  vogue  and  was  justly  regarded  as  a  most 
important  defence  against  small-pox ;  and  until  the  milder 
method  of  inoculating  "vaccine  "  matter,  i.e.  matter  derived 
from  the  cow,  was  devised  by  Jenner,  no  other  method  of 
prevention  of  small-pox,  or,  for  that  matter,  of  any  infec- 
tious disease,  was  known  or  practised. 

The  attitude  of  mankind  at  various  times  toward  small- 
pox, inoculation  and  vaccination  forms  one  of  the  most 
remarkable  chapters  in  the  history  of  the  human  race.  It 
is  impossible  to-day  to  realize  the  dread  and  awful  terror 
with  which  this  horrible  and  most  loathsome  disease  was 
justly  regarded  by  our  ancestors  before  the  introduction  of 


78    THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

inoculation  and  vaccination.  A  single  brief  quotation  may 
help  to  give  the  reader  some  idea  of  the  feeling  in  regard 
to  it  and  its  prevalence,  even  as  late  as  the  middle  of  the 
eighteenth  century.  "Small-pox  has  been  for  ages,  and 
continues  to  be,  the  terror  and  destroyer  of  a  great  part  of 
mankind.  ...  In  the  ordinary  course  and  duration  of 
human  life  scarce  one  in  a  thousand  escapes  the  small- 
pox." .  .  .  (Appendix  to  Dr.  Brooke's  "General  Practice 
of  Physic,"  London,  1766.)  It  would  be  easy  to  multiply 
authoritative  statements  of  the  fearful  ravages  of  this  dis- 
ease, and  to  bring  forward  testimony  to  its  abundance, 
contagiousness  and  foul  character.  Fortunately,  it  has 
become  to-day  in  civilized  countries  so  uncommon  that  the 
former  dread  of  it  has  largely  disappeared  from  the  popu- 
lar mind.  Unfortunately,  however,  unfamiliarity  with  it 
has  bred  a  contempt  for  it  which  leads  many  to  despise, 
undervalue  or  refuse  the  means  by  which  it  is  chiefly  kept 
in  abeyance.  Such  contempt  is  likely,  if  it  becomes  gen- 
eral, to  carry  with  it  its  own  punishment,  for  small-pox  is 
so  contagious  tl^t  its  recrudescence  at  any  time  in  any 
community  is  na^ral  and  easy,  if  the  very  simple  means  in 
our  possession  for  holding  it  in  check  are  long  neglected. 

The  art  of  inoculation  for  the  prevention  of  small-pox  appears  to 
have  been  long  known  and  to  have  come  to  Constantinople  from  the 
East  —  from  the  Circassians  in  one  direction  and  from  the  Chinese  in 
another.  By  the  Chinese  the  dried  pustules  are  said  to  have  been  kept 
in  bottles,  inoculation  being  produced,  when  desired,  by  placing  por- 
tions of  these  pustules  in  the  nose  of  the  patient. 

The  results  of  inoculation  appear  to  have  been  remarkably  success- 
ful and  under  favorable  circumstances  to  have  approached,  though  they 
did  not  equal,  those  attained  by  vaccination.  Sir  George  Baker,  a  dis- 
tinguished authority,  writing  in  1766,  affirms,  "According  to  the  best 
information  which  I  can  procure,  about  seventeen  thousand  have  been 
thus  inoculated,  of  which  number  no  more  than  five  or  six  have  died.1" 
Another  writer  of  the  same  time  says,  "  Scarce  one  in  one  hundred 
miscarries,  whereas  a  fifth  or  a  sixth  part  die  of  the  natural  small-pox." 
Dr.  Hadow,  of  Warwick,  is  said  to  have  practised  inoculation  for 
twenty-seven  years,  and  out  of  2143  persons  inoculated  only  three 


"INOCULATION"  AGAINST   SMALL-POX  79 

(children)  died  :  of  these  one  of  an  overdose  of  opium,  one  in  very  hot 
weather,  the  third  of  nose  bleed. 

Much  importance  was  attached  by  the  best  practitioners  to  "  pre- 
paratory treatment  "  of  various  kinds,  although  in  the  East  this  was 
less  regarded.  Sir  George  Baker  quotes  Gatti,  "  who  some  time  ago 
was  much  employed  in  inoculation  at  Paris "  as  "  an  enemy  to  any 
general  plan  of  preparation.  In  all  the  Levant,  he  says,  where  the 
natural  small-pox  is  as  fatal  as  elsewhere,  and  where  you  may  find 
old  women  who  have  inoculated  ten  thousand  people  without  an 
accident,  the  only  inquiry  is,  whether  or  no  a  person  is  prepared  by 
Nature.  All  that  is  considered  is  whether  the  breath  be  sweet,  the 
skin  soft,  and  whether  a  little  wound  in  it  heals  easily.  Whenever 
these  conditions  are  found,  they  inoculate  without  the  least  apprehension 
of  danger."  ("  An  Inquiry  into  the  Merits  of  a  Method  of  Inoculating 
the  Small-pox,"  etc.,  London,  1766.)  In  America,  where  inoculation 
was  also  much  practised  before  the  introduction  of  vaccination,  prepar- 
atory treatment  was  common,  and  Sir  George  Baker  (/.  c.~)  states  on  the 
authority  of  Dr.  Huxham  that  "Dr.  Benjamin  Gale,  of  Connecticut,  in 
New  England,  since  he  has  given  mercury  and  antimony  in  preparing 
persons  for  inoculation,  has  lost  only  one  person  out  of  eight  hundred 
inoculated."  (On  inoculation  in  New  England,  see  Dr.  Zabdiel  Boylston 
"An  Historical  Account,"  etc.,  Boston,  1730;  in  Massachusetts,  see  J. 
M.  Toner,  in  Mass.  Med.  Soc.  Trans.,  Vol.  II,  p.  151,  Boston,  1867 ;  in 
Great  Britain,  see  W.  Woodville,  "  Hist.  Inoc.  Small-pox,"  etc.,  London, 
1796.)  For  Dr.  Gale's  paper  see  Phil.  Trans.  Roy.  Soc.,  London,  1765. 

The  drawback  to  inoculation  was  that  persons  inoculated  had  for  the 
time  being  mild  cases  of  genuine  small-pox,  and  were  therefore  capa- 
ble of  conveying  the  disease  to  others.  They  became,  temporarily 
at  least,  "  foci  of  infection,"  and  were  usually  treated  as  such,  being 
often  gathered  together  in  inoculation  "  hospitals  "  or  establishments 
in  relatively  remote  and  inaccessible  places,  and  kept  meanwhile  under 
more  or  less  strict  quarantine  regulations.  Those  who  voluntarily  re- 
sorted thither  for  inoculation  naturally  went,  or  were  sent,  while  in  good 
health  or  well  "  prepared,"  and,  for  the  time  being,  were  completely 
separated  from  their  families.  It  was  a  successful,  but  rather  dangerous 
and  troublesome  method  of  combating  the  disease,  and  when  vaccina- 
tion, equally  and  perhaps  more  protective  and  neither  difficult  nor 
dangerous,  was  introduced  (in  1796),  inoculation  fell  into  disrepute  and 
was  finally  forbidden  by  law  (in  1840,  in  England).  Like  its  successor 
and  superior,  inoculation  of  cow-pox  (vaccination),  the  practice  of 
inoculation  of  small-pox  met  with  strenuous  contemporary  opposition, 
but  the  esteem  in  which  it  was  held  by  the  most  eminent  physicians 
and  scientific  men  of  the  time  is  sufficient  evidence  of  its  value.  "  It 


80    THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

cannot  be,  likewise  it  ought  not  to  be,  concealed  that  some  of  the 
inoculated  have  died  under  this  process  even  under  the  care  of  very 
able  and  experienced  practitioners.  But  this  number  is  so  small  that 
when  compared  with  the  mortality  attending  the  natural  smallpox  it 
is  reduced  almost  to  a  cypher."  (Dimsdale,  "The  Present  Method 
of  Inoculating  for  the  Smallpox,"  etc.,  London,  1767). 

Inoculation  for  small-pox  will  always  remain  for  the 
student  of  hygiene  one  of  the  most  interesting  episodes  in 
the  development  of  sanitary  science,1  for  it  illustrates  in  the 
clearest  manner  some  of  the  fundamental  phenomena  of 
infection,  susceptibility,  vital  resistance  and  immunity  — 
and  these  are  among  the  principal  problems  of  hygiology. 

§  10.  —  Vaccination 

Vaccination  (Vacca,  cow)  is  simply  a  modification  of 
inoculation  in  which  "  matter  "  of  cow-pox  taken  originally 
from  the  cow  is  substituted  for  "  matter "  of  small-pox 
taken  from  man.  It  is  immaterial  for  our  present  purpose 
whether  cow-pox  is  or  is  not  small-pox  in  the  cow.  The 
important  fact  is  that  inoculation  of  the  matter  of  cow-pox 
into  the  body  of  human  subjects  is  believed  by  those  most 
competent  to  pronounce  an  opinion  to  prevent  or  weaken 
the  virulence  of  small-pox  in  such  subjects.  Experts  are 
unanimous  in  this  opinion,  and  the  methods  and  results  of 
vaccination — the  immortal  discovery  of  Jenner  in  1796 — 
are  too  familiar  to  require  comment.  By  its  universal 
application  small-pox,  as  experience  shows,  can  be  not 
only  held  in  check  but  virtually  exterminated. 

In  its  infancy  vaccination,  like  inoculation,  had  to  en- 
counter strong  opposition  based  upon  ignorance  and  a 
natural  dread.  "  Discoveries  in  physic,  as  in  every  other 

1  Jonathan  Edwards,  the  famous  New  England  theologian,  was  installed  as 
President  of  Princeton  College  on  February  16,  1758,  when  small-pox  was 
prevailing  in  the  neighborhood.  As  an  act  of  precaution  he  was  inoculated, 
although  after  some  hesitation  and  while  he  was  in  poor  physical  condition, 
and  died  thirty-four  days  after  his  inauguration. 


"VACCINATION"   AGAINST   SMALL-POX  8 1 

science,  are  in  their  infancy  liable  to  censure  and  opposi- 
tion ;  and  as  the  present  system  of  inoculation  is  of  so 
extraordinary  a  kind,  it  would  not  be  strange  if  a  greater 
portion  of  both  than  usual  should  fall  to  its  share." 
(Dimsdale,  /.  c.,  1767.)  The  remarkable  fact  is  that  long 
after  its  success  has  been  abundantly  demonstrated,  and 
after  its  period  of  "  infancy  "  may  be  regarded  as  having; 
been  long  since  passed,  the  practice  of  vaccination  should 
still  be  not  only  rejected  but  also  violently  attacked  by  some 
persons  of  intelligence.  The  fundamental  reason  for  this 
paradoxical  state  of  things  is,  doubtless,  that  assigned  above 
by  Baron  Dimsdale,  namely,  the  "  extraordinary  "  character 
of  a  treatment  which  consists  in  "  inoculation  "  of  any  kind. 
Persons  who  of  their  own  motion  or  on  the  advice  of  their 
physicians  will  cheerfully  and  even  eagerly  swallow  "  medi- 
cines," often  of  a  poisonous  character,  the  very  names  of 
which  are  unknown  to  them,  will  sometimes  refuse  to  obey 
their  medical  advisers  when  these  recommend  vaccination, 
—  the  former  custom  being  "  ordinary  "  and  hoary  with  age, 
the  latter  still  comparatively  novel  and  "  extraordinary." 

The  precise  mechanism  of  that  immunity  which  is  the 
most  remarkable  and  most  valuable  sequel  of  inoculation 
(or  vaccination)  is  still  a  mystery.  Some  light,  however, 
has  been  shed  upon  the  problem  by  the  discoveries  of 
Pasteur,  Metschnikoff  and  Behring,  and  their  successors,  to 
a  consideration  of  which  we  may  now  turn.1  (Cf.  p.  318.) 

§  ii. — Pasteur  and  Attenuation 

While  germs  or  microbes  characteristic  of  small-pox  or 
of  cow-pox  have  never  yet  been  satisfactorily  isolated, 
analogy  compels  us  for  the  present  to  assume  their  exist- 
ence. A  consideration  of  the  corollaries  resulting  from  the 
application  of  the  germ  theory  to  these  long-known  and 

1  For  an  excellent  short  modern  treatise,  see  "  Vaccination,"  by  S.  M. 
Copeman  (Macmillan),  1899. 


82     THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

world-famous  diseases  led  Pasteur,  in  1877,  not  indeed  to 
a  solution  of  the  problem  of  immunity,  but  to  an  important 
extension  of  the  art  of  vaccination,  and  new  and  inter- 
esting examples  of  the  immunity-phenomenon.  Pasteur 
reasoned  that,  if  an  infectious  disease  be  really  a  struggle 
for  supremacy  between  man  and  microbe,  it  is  probable 
that  in  vaccination  for  small-pox  the  struggle  is  less  severe 
for  the  patient  because  the  germs  of  small-pox  have  some- 
how been  weakened  or  enfeebled  by  their  residence  in  the 
cow.  If  this  hypothesis  were  correct,  he  might  hope  to 
lessen  the  virulence  of  any  microbe  by  subjecting  it  to  an 
unfavorable  environment  or  treatment.  Heat,  cold,  dilu- 
tion, starvation,  overfeeding,  etc.,  suggest  themselves  as 
possible  agents  for  weakening  virulence;  and  by  experi- 
ment Pasteur  actually  produced  enfeebled  or  "  attenuated  " 
cultures  of  anthrax,  chicken  cholera,  etc.,  with  which  he 
was  able  successfully  to  "  vaccinate  "  (if  the  term  may  still 
be  used)  various  animals,  rendering  them  more  or  less 
immune  to  the  diseases  respectively  investigated.  In  a 
dramatic  public  demonstration,  in  1880,  Pasteur  proved 
conclusively  the  practicability  of  his  method,  which,  since 
that  time,  has  passed  into  common  use  in  France  for  the 
vaccination  of  domestic  animals.1  (Cf.  pp.  321-324.) 

As  a  result  of  Pasteur's  labors,  fresh  examples  of  immu- 
nity were  provided,  and  the  practicability  of  its  artificial  pro- 
duction was  strongly  emphasized ;  but  the  basis  of  immunity 
or  the  physiological  mechanics  by  which  it  comes  to  pass 
and  persists  remained  as  great  a  mystery  as  ever. 

§  12.  —  Metschnikoff  and  Phagocytosis 

A  highly  ingenious  theory  of  immunity  was  suggested 
in  1882  by  E.  Metschnikoff,  who,  starting  with  the  well- 
known  fact  that  the  white  blood-cells  are  eating-cells  (or 

1  See  "  Louis  Pasteur :  His  Life  and  Labors"  (Radot),  New  York,  Apple- 
ton,  1885,  pp.  220-246. 


THE   STRUGGLE  OF  MAN  WITH   MICROBE          83 

pfuigocytes]  and  readily  devour  yeast-cells,  bacteria-cells, 
etc.,  made  elaborate  and  important  investigations  tending 
to  show  that,  in  the  struggle  between  man  and  microbe 
which  may  be  said  to  constitute  the  essence  of  an  infec- 
tious disease,  the  battle  is  really  between  the  white  blood- 
cells  and  the  microbes,  after  the  latter  have  somehow- 
secured  entrance  into  the  body  proper,  and  especially  into 
the  blood-vessels.  MetschnikofF s  theory  of  immunity  is 
therefore  known  as  the  theory  of  phagocytosis.  It  has 
the  merits  of  simplicity  and  picturesqueness ;  but,  while 
doubtless  containing  much  that  is  true,  it  fails  at  one  of  the 
most  important  points,  namely,  in  explaining  the  persistence 
of  immunity  long  after  the  disease  is  over  except  indeed 
on  the  somewhat  too  anthropomorphic  theory  that  the  pha- 
gocytes have  become  "trained"  or  "educated."  It  fails, 
also,  to  account  satisfactorily  for  some  of  the  remarkable 
phenomena  afforded  by  blood-serum  experiments,  such  as 
those  now  to  be  described. 

§  13. — Behring  and  Antitoxic  Serums 

In  1892  an  entirely  new  line  of  experiment  was 
opened  up  by  Behring  and  Kitasato  in  their  work  on  diph- 
theria. It  was  discovered  by  them  that  the  serum  of  an 
animal  which  had  been  made  immune  to  the  toxin  of  diph- 
theria was  able,  even  in  a  test-tube,  to  neutralize  or  impair 
the  virulence  of  such  a  toxin,  and  further  that  the  serum 
of  a  non-immune  animal  was  not  able  to  do  this.  Clearly, 
then,  substances  exist  in  the  serum  of  an  immune  animal 
which  were  not  there  before  the  process  of  immunization, 
and  our  present  theory  of  immunity  rests  upon  this  fact. 
The  process  of  immunization  according  to  the  serum  theory 
may  be  described  as  follows :  the  microbe  (or  its  toxin) 
irritates  the  cells  of  its  host ;  these  produce  defensive  sub- 
stances or  antidotes  (antitoxins),  which  tend  to  neutralize 
the  poison,  or  to  inhibit  the  activity,  of  the  microbe,  or  both. 


84     THE  "STRUGGLE  FOR  EXISTENCE"  AND  DISEASE 

If  we  assume  victory  for  the  cells,  we  have  temporary  im- 
munity or  convalescence.  Victory  for  the  microbe  means 
continued  disease  or  death.  If  we  may  assume  that  the 
cells  of  the  body  continue  to  secrete  more  or  less  of  the 
defensive  substances,  or  that  they  remain  for  a  long  time 
peculiarly  sensitive  to  even  minute  doses  of  the  toxin  in 
question,  we  can  understand  the  persistence  of  more  or 
less  immunity.  But  these  assumptions,  while  plausible  and 
perhaps  reasonable,  are  purely  hypothetical. 

If  we  assume,  as  we  may  if  we  like,  that  the  phagocytes 
of  Metschnikoff  are  the  principal  productive  sources  of 
antitoxic  substances,  we  have  a  certain  harmony  between 
the  two  rival  theories  which  is,  to  say  the  least,  conceivable. 
Much,  however,  remains  to  be  done  before  any  theory  of 
immunity  can  be  received  as  more  than  very  imperfectly 
explaining  all  of  the  facts.1 


§  14.  —  Serum  as  Ctire  and  Serum  as  Prevention 

The  practical  outcome  of  Behring's  work  has  been  of 
immense  importance,  especially  in  the  cure  and  prevention 
of  diphtheria.  Patients  suffering  from  this  disease,  and 
persons  exposed  or  likely  to  be  exposed  to  it,  may  and  do 
have  their  own  antitoxic  serum  reenforced  by  the  antitoxic 
serum  of  the  horse  or  other  immune  animal  and  thus  are 
materially  aided  in  their  battle  with  the  microbes.  The 
process  is  simple.  Microbes  of  diphtheria  are  cultivated 
in  a  richly  nutrient  liquid  which  gradually  becomes  charged 
with  their  toxin.  The  liquid  is  filtered,  and  portions  of 
the  toxin-bearing  filtrate  are  subcutaneously  injected  into 
horses,  beginning  with  small  doses  and  continuing  until  the 
animal  is  immune  to  large  doses.  Blood  is  then  drawn 
from  the  immune  horse,  and  the  serum  from  this  blood  is 

1  For  further  remarks  on  Vital  Resistance  and  Immunity,  see  Chapter  V, 
§  6,  and  Chapter  XIII. 


REVIEW   OF  THE  ZYMOTOXIC  THEORY  85 

found  to  contain  antitoxin  in  abundance.  This  serum  is 
carefully  filtered  and  then  used  subcutaneously  as  a  ree'n- 
forcing  remedy  for  persons  actually  ill  with  diphtheria,  or 
as  a  preventive  medicine  by  those  who  either  may  be  or 
may  have  been  "  exposed  "  to  it.  The  results  of  the  serum  T 
treatment  have  everywhere  been  most  significant  and 
encouraging. 

§15.  —  Recapitulation 

This  brief  statement  of  our  present  attitude  in  respect  to 
infectious  disease  must  suffice  for  the  student  of  sanitary 
science.  Those  who  desire  to  go  further  along  these  lines 
should  consult  the  numerous  excellent  manuals  of  bacteri- 
ology, in  which  they  will  find  a  rich  store  of  materials  to 
draw  upon.  It  is  enough  for  the  student  of  sanitary 
science  to  know  that  infectious  diseases  are  now  believed 
never  to  arise  spontaneously  or  de  novo,  but  only  more  or 
less  directly  from  antecedent  cases  of  the  same  disease. 
It  is  believed  that  in  every  instance  there  must  be  an 
actual  invasion  of,  or  at  least  contact  with,  the  suscepti- 
ble patient  by  the  micro-organism  of  the  disease  in  ques- 
tion. Once  inside  or  upon  the  patient,  the  micro-organisms 
may  grow  and  multiply,  producing  at  the  same  time  their 
own  peculiar  toxin  or  toxins,  precisely  as  yeast,  whether  in 
wine  or  beer  or  other  fruit  juices,  produces  alcohol  as  one 
outcome  of  its  peculiar  vital  activity.  The  illness  of  the 
patient  is  believed  to  be  due  to  the  effect  upon  his  body  of 
these  specific  poisons,  by  which  he  may  die,  or  to  which  he 
may  become  habituated.  In  the  latter  case  he  is  said  to 
be  immune,  very  much  as  the  smoker  becomes  immune  to 
considerable  doses  of  tobacco,  or  the  arsenic  eaters  of 
Styria  to  heavy  doses  of  arsenic,  or  opium  eaters  to  opium. 
The  physiological  mechanism  of  immunity  is  still  to  a  great 
extent  a  mystery,  but  one  feature  of  it  appears  to  be  a 
cellular  reaction  to  the  foreign  toxin,  accompanied  by  the 
production  of  antidotal  substances  (antitoxins)  capable  of 


86    THE  «  STRUGGLE  FOR  EXISTENCE  "  AND  DISEASE 

neutralizing  the  microbic  poisons  (toxins).  Whether  the 
cells  once  affected  may  be  said  to  have  become  "  habitu- 
ated "  to  the  poison,  and  if  so  what,  precisely,  such 
"  habituation "  means,  is  less  clear,  and  further  investiga- 
tions are  required  to  elucidate  this  part  of  the  problem. 
Meantime  the  practical  value  of  the  work  already  done  is 
very  great,  and  the  antitoxic  serum  for  diphtheria  has 
become  one  of  the  most  important  weapons  of  the  physi- 
cian and  the  sanitarian.1 

1  The  author  is  indebted  to  Dr.  J.  H.  McCollom,  Instructor  in  Contagious 
Diseases  in  Harvard  University,  and  Resident  Physician,  South  Department 
(Contagious  Diseases),  Boston  City  Hospital,  for  the  following  facts:  — 

Before  the  advent  of  antitoxin  the  fatality  in  cases  of  diphtheria  (in  hos- 
pitals) varied  from  30  to  50  per  cent.  In  11,598  cases  in  the  Asylums'  Board 
Hospitals,  London,  without  antitoxin,  it  was  30.3  per  cent.  In  the  same 
hospitals,  with  antitoxin,  it  has  been  18.4  per  cent.  In  the  Boston  City  Hos- 
pital, without  antitoxin,  the  recent  fatality  was  46  per  cent;  with  antitoxin, 
it  has  been  12.9  per  cent.  Bayeux,  in  his  work  on  diphtheria,  gives  55  per 
cent  without,  and  16  per  cent  with,  antitoxin,  the  latter  figure  being  based 
on  an  analysis  of  more  than  200,000  cases.  Bayeux  adds  that  not  a  single 
death  has  been  clearly  demonstrated  to  have  been  due  to  the  use  of  the 
serum. 

Other  statistics  may  be  found  in  Quar.  Pub.  American  Statistical  Assoc., 
VH»  53  (June,  1901),  and  in  ^zd  Ann.  Rep.  State  Board  of  Health  of  Massa- 
chusetts, for  1900,  p.  768. 


PART   II 

INFECTION  AND   CONTAGION:    THEIR 
DISSEMINATION  AND  CONTROL 


CHAPTER  V 

ON  INFECTION  AND  CONTAGION  :  THE  PATHS  AND  PORTALS 
BY  WHICH  THEY  ENTER  THE  BODY;  THE  RESISTANCE 
WHICH  THE  BODY  OFFERS;  THE  VEHICLES  BY  WHICH 
THEY  ARE  CONVEYED ;  AND  THE  PLACES  OF  THEIR  ORIGIN. 
ANIMALS  AND  THEIR  EXCRETA  AS  SOURCES  AND  PRIME 
MOVERS  OF  INFECTION 

"  Fur  die  Verbreitungsweise  der  Infectionskrankheiten  kommen 
zunachst  in  Betracht  die  Infectionsquellen,  die  Transportwege,  welche 
von  dort  zum  Menschen  fiihren,  und  die  Invasionsstatten,  an  welchen 
das  Eindringen  der  Infectionserreger  in  den  gesunden  Kb'rper  erfolgt. 
Sodann  haben  wir  der  individuellen  Disposition  und  der  Immunitat 
besondere  Beachtung  zu  schenken,  da  diese  Momente  die  Verbrei- 
tungsweise mancher  Infectionskrankheiten  in  hohem  Grade  beeinflus- 
sen." — FLUGGE. 

"  Exact  scientific  knowledge  of  the  contagia  and  of  their  respective 
modes  of  operation  is  of  supreme  importance  to  the  prevention  of 
disease.  With  even  such  knowledge  of  them  as  already  exists  diseases 
which  have  in  past  times  been  most  murderous  ....  can,  if  the 
knowledge  be  duly  applied,  be  kept  in  subjection."  —  SIMON. 

§  I. — Infection ,  Infectious  Substances  and  Infectious 
Diseases 

IN  order  that  apple  juice  shall  be  fermented  by  yeast 
micro-organisms  must  somehow  find  access  to  it.  But  the 
normal  apple  is  protected  from  the  invasion  of  yeast  both 
by  its  skin  —  a  mechanical  or  structural  defence  —  and 
probably  also  by  specific  properties  of  its  living  cells,  which 
properties,  though  they  are  not  understood,  are  recognized 
and  described  by  the  term  "  vital  resistance."  The  skin  of 
the  apple  must  be  broken  and  vital  resistance  overcome 

89 


90  ON   INFECTION   AND   CONTAGION 

before  yeast  can  make  its  way  into  either  juices  or  tissues, 
successfully  "  infecting  "  them  and  producing  those  changes 
which  we  call  fermentation.  It  may  even  be  said  that  the 
apple  is  "  hermetically  sealed  "  by  its  skin,  for  no  sound 
apple  can  be  infected  or  fermented  by  yeast  unless  its 
body  has  been  penetrated  either  by  living  yeast  cells  or 
else,  what  is  yet  an  open  question,  by  soluble  and  diffusi- 
ble products  of  yeast. 

The  word  "  infection "  (from  in  and  facere)  signifies 
"  entrance "  or,  literally,  "  making  into,"  and  in  sanitary 
science  it  means  in  the  first  place,  a  process,  namely,  the 
entrance  into  a  living  body,  whether  plant  or  animal,  of 
something  capable  of  producing  disease.  Contagion,  as 
will  be  explained  presently,  is  only  a  special  kind  of  infec- 
tion. The  words  "infection"  and  "  contagion  "  are  also 
used,  in  the  second  place,  in  another  sense,  substantively,  — 
"the  infection,"  "  the  contagion,"  —  to  represent  the  infec- 
tious or  contagious  material  itself.  From  what  has  been 
said  in  the  preceding  chapters  it  is  plain  that  infection  of 
the  human  body  is  usually  its  invasion  by  parasitic  micro- 
organisms, each  specific  invasion  constituting  a  specific 
infection ;  and  the  "  infectious  diseases  "  are  those  which 
are  produced  by  such  invasions.  The  term  "  communica- 
ble "  is  also  much  used  for  this  group  of  diseases.  In 
practice  the  word  "infection,"  when  used  for  infectious 
materials,  is  usually  applied  to  living  materies  morbi  capa- 
ble of  growth  and  multiplication  in  the  body  of  the  infected 
plant  or  animal  and  of  transfer  from  one  victim  to  another. 
Etymologically  speaking,  to  be  sure,  it  might  be  applied 
also  to  inorganic  matters  such  as  metallic  poisons,  —  lead, 
copper,  arsenic,  etc.,  —  or  to  organic  but  lifeless  poisons,  — 
such  as  the  venom  of  serpents,  the  vegetable  alkaloids, 
etc.,  —  introduced  in  any  way  into  the  living  organism  ;  but 
as  these  are  doubtless  also  communicable  (though  rarely 
communicated),  either  term  may  be  used  at  will,  both  being 
clearly  inferior  in  descriptive  accuracy  to  the  term  "zy- 


DEFINITIONS  91 

motic,"  which,  after  all,  is  probably  the  most  correct  and 
comprehensive  name  for  those  diseases  which  are  essen- 
tially attacks  upon  the  plant  or  animal  body  by  living  fer- 
ments. That  these  ferments  happen  also  to  be  more  or 
less  readily  "  communicable  "  is  an  incident  only  and  not 
their  principal  characteristic ;  and  that  they  are  "infectious," 
or  capable  of  entering  the  body,  is  a  property  which  they 
share  with  diseases  caused  by  other  environmental  agen- 
cies, such  as  lightning,  arsenic  and  toadstools  mistaken  for 
mushrooms. 

§  2.  —  The  Skin  and  Epithelia  as  Structural  Defences  of 
the  Living  Body  against  the  Invasions  of  Disease 

As  the  normal  apple  is  protected  by  its  covering  or 
skin,  so  the  normal  living  body  is  protected  by  its  cover- 
ings —  skin  and  epithelia  —  from  the  invasion  of  parasitic 
or  fermentative  micro-organisms  or  their  products.  It  is 
perhaps  too  much  to  say  that  the  living  body  is  hermetically 
sealed,  and  yet  modern  physiology  teaches  that  one  of  the 
principal  offices  of  the  skin  is  protection  against  forces  or 
substances  acting  from  without,  and  that  the  cells  of  the 
more  delicate  epithelia  covering  the  lung  surfaces  and  the 
alimentary  and  genito-urinary  tracts  have  as  one  of  their 
specific  duties  a  certain  discriminating  authority  over  the 
matters  likely  to  pass  through  or  to  be  absorbed  by  them. 
In  somewhat  more  than  a  metaphorical  sense,  therefore, 
it  may  be  safe  to  say  that  the  living  animal  body  is  her- 
metically sealed  against  the  invasion  of  matters  proceed- 
ing from  the  environment.  The  phrase,  once  much  used, 
which  referred  to  any  rupture  of  this  seal  as  a  "  solution 
of  continuity  "  undoubtedly  referred  to  the  same  idea,  and 
marks  the  recognition  of  the  essential  integrity  of  the  body 
surfaces  as  one  condition  of  health. 

In  order  that  any  germ,  whether  parasitic  or  not,  shall 
find  entrance  into  the  living  body,  it  must  be  able  some- 


92  ON   INFECTION   AND   CONTAGION 

how  to  pass  through  the  ordinary  defences.  In  the  case 
of  the  skin  it  would  appear  that  an  actual  rupture  must 
take  place,  as  happens,  for  example,  in  a  puncture,  incision, 
bruise  or  other  mechanical  injury.  In  the  case  of  the 
epithelia,  it  may  be  that  a  similar  passage  by  force  is  neces- 
sary, or  it  may  be  that  the  living  cells  which  here  line  the 
surface  externally  are,  so  to  speak,  off  their  guard  or  for 
the  time  being  actually  facilitate  an  invasion  which,  from 
their  delicacy,  is  here  more  easily  effected.  At  any  rate, 
it  is  easy  to  see  that  for  the  actual  entrance  of  micro- 
organisms into  the  body  proper  an  unusual  and  direct 
passage  must  somehow  be  provided.  As  to  the  absorp- 
tion of  the  toxic  products  of  germ  life  we  shall  have  some- 
thing to  say  in  §  5. 

It  should  not  be  forgotten  that  by  "  the  body  proper  " 
is  meant  that  portion  of  it  enclosed  within  the  skin  and 
epithelia;  the  cavities  of  the  alimentary  canal  and  the 
genito-urinary  tracts  not  being  included,  inasmuch  as  they 
are  really  portions  of  the  environment  merely  passing 
through  or  dipping  into  the  body-mass. 

§  3.  —  Infection  by  Way  of  the  Skin.     Invasion  by  Force 

The  processes  of  infection  by  way  of  the  alimentary  canal 
and  the  genito-urinary  tract,  to  be  described  in  §  5,  are  typi- 
cal of  a  large  class  of  the  more  obscure  infectious  diseases. 
There  is,  however,  another  and  commoner  path  by  which 
micro-organisms  obtain  entrance  into  the  body  proper,  and 
that  is  directly  through  the  skin,  the  diseases  to  which  they 
give  rise  being  known  as  "wound"  diseases.  Many  of 
these  are  familiar,  as,  for  example,  the  results  of  simple 
punctures  made  by  small  foreign  bodies  such  as  pins, 
needles,  "  slivers  "  and  the  like.  When  these  carry  in  with 
them  micro-organisms  capable  of  setting  up  fermentation 
or  inflammation,  the  infection  thus  produced  may  be  either 
local  or  general :  in  the  former  case  leading  to  the  condi- 


SKIN  AND  EPITHELIA  AS  PORTALS  OF  INFECTION     93 

tions  familiar  in  such  unimportant  local  wounds  as  those 
mentioned ;  in  the  latter  to  septicaemia,  or  dangerous  blood 
poisoning,  a  kind  of  fermentation  of  the  whole  body.  Occa- 
sionally it  happens  that  a  wound  made  by  a  sliver  or  some 
other  ordinarily  insignificant  object,  such  as  a  needle  or  a 
bee  sting,  is  followed  not  merely  by  the  usual  local  inflam- 
mation, but  by  a  far  more  serious  and  extensive  injury  and 
even  by  speedy  death.  It  is  supposed  that  in  these  cases 
either  the  infection  was  of  an  unusual  and  severe  type  — 
by  which  is  meant  that  the  micro-organisms  were  unusually 
abundant  or  of  some  unusually  virulent  species  —  or  else 
that  the  vital  resistance  of  the  cells  and  tissues  of  the  victim 
happened  to  be  poor  in  kind  or  at  a  low  ebb,  so  that  even 
ordinary  micro-organisms  met  with  specially  favorable 
conditions.  In  a  word,  either  the  infection  was  unusually 
powerful  or  the  patient  was  unusually  susceptible.  It  is, 
of  course,  possible  to  conceive  of  a  third  condition  resulting 
from  an  unfortunate  coincidence  or  combination  of  the 
other  two. 

§  4.  —  Wounds  and  the  Diseases  of  Wounds 

The  punctures  and  other  simple  infections  by  way  of 
the  skin  just  described  belong  in  the  same  class  with 
more  serious  interruptions  of  continuity  such  as  gun-shot 
wounds,  compound  fractures,  abrasions  and  the  like,  among 
which  must  be  classified  as  of  the  highest  practical  im- 
portance surgical  operations  such  as  excisions  of  tumors, 
amputations,  the  tying  of  arteries,  etc.  In  these  cases  the 
bullet,  the  surgeon's  or  dissector's  knife,  or  other  foreign 
body  of  relatively  large  size,  may  readily  be  a  vehicle  for 
the  germs  of  infectious  disease.  It  has  already  been 
pointed  out  how  the  classical  inductions  of  Lister  and  his 
application  of  the  germ  theory  and  its  corollaries  to  this 
class  of  diseases  has  led  to  results  of  the  first  importance 
in  this  direction,  namely,  to  sanitary  or  aseptic  surgery. 
(See  p.  45.) 


94  ON  INFECTION  AND  CONTAGION 

There  is  one  disease  of  wounds  particularly  interesting, 
for  various  reasons,  to  the  sanitarian  as  well  as  to  the  sur- 
geon, namely,  tetanus  or  "  lock-jaw."  It  had  long  been 
known  from  observation  and  experience  that  certain  punc- 
tures or  incisions,  especially  those  made  by  the  entrance  or 
laceration  effected  by  dirty  foreign  bodies,  were  not  infre- 
quently followed  by  a  peculiar  condition  of  the  patient  in 
which  tetanic  muscular  spasms  were  a  prominent  feature, 
when,  in  1884,  Neisser  isolated  from  garden  soil  a  bacillus 
capable  on  inoculation  into  mice  and  rabbits  of  producing 
a  similar  disease.  Further  investigations  have  confirmed 
the  discovery,  and  the  natural  history  of  the  Bacillus  tctani 
is  now  well  known.  It  is  frequently  found  in  the  earth 
and  it  is  widely  distributed  in  nature.  It  is  anaerobic,  /.<?., 
it  thrives  best  in  the  complete  absence  of  oxygen.  Culti- 
vated in  bouillon,  it  produces  a  powerful  poison  (toxin) 
which  appears  to  realize  the  early  speculations  of  Dr.  Farr,1 
and  which,  even  in  the  absence  of  all  living  bacteria,  is 
capable  of  producing  typical  tetanic  convulsions.  A  sub- 
stance apparently  identical  with  it  has  been  separated  from 
the  muscles  of  patients  dead  of  tetanus,  and  this  substance, 
when  injected  into  the  lower  animals,  produces  in  them 
tetanic  spasms.  It  may  be  added  that  an  antitoxin  capa- 
ble of  neutralizing  the  toxin  of  tetanus  has  more  recently 
also  been  prepared  and  used. 

The  importance  of  the  bites  and  stings  or  other  punc- 
tures of  the  skin  by  insects,  which  has  long  been  recog- 
nized theoretically,  has  recently  received  fresh  emphasis 
and  attention,  owing  to  the  results  of  investigations  upon  the 
hitherto  obscure  but  widespread  disease  known  as  malaria. 
It  is  now  believed  that  the  female  of  a  species  of  mosquito 
is  the  principal  vehicle  of  this  disease  ;  that  the  mosquito 
becomes  itself  inoculated  by  drawing  the  blood  of  malarial 
human  subjects  in  whom  the  germ  of  malaria  exists,  often 
in  the  red  blood-cells ;  that  in  the  mosquito  the  malarial 

1  "Vital  Statistics,"  I.e.,  pp.  244-245. 


FlG.  I.  (After  Leuckart-Chun's  Wall-Diagram.)  —  ANOPHELES  AND  THE  MALARIA 
GERM,  i,  2.  The  malaria  germ  (Plasm odium)  introduced  by  a  mosquito  bite 
into  human  blood.  3-5.  After  penetrating  a  red-blood  cell ;  its  growth  at  the 
expense  of  the  latter.  6.  Its  vegetative  multiplication.  7,  8.  Crescentic  forms 
(for  further  development  the  germs  must  at  this  point  be  transferred  from  the 
man  to  mosquito).  9.  Female  germ-cell;  9  a,  9  b,  Male  germ-cell.  10.  Conju- 
gation of  9  with  one  of  the  vibratile  arms  of  gb.  n.  Malaria  germ  resulting 
from  such  conjugation  in  stomach  of  mosquito.  12-16.  Multiplication  (encyst- 
ment  and  sporulation)  of  the  malaria  germ  in  the  body  of  the  mosquito,  with 
production  of  many  forms  like  i  (cycle  completed).  17.  Female  malarial  mos- 
quito (Anopheles  claviger)  ;  head  of  male  below.  19-20.  Mosquito  larva  and 
pupa.  21.  Stomach  of  mosquito,  showing  tumors  produced  by  16.  22.  Cross- 
section  of  salivary  gland  of  mosquito,  showing  malarial  microbes  which  have 
wandered  into  it  (from  the  tumors  in  21)  and  now  ready  to  be  transferred  with 
saliva  into  persons  bitten. 


MOSQUITOES,  MALARIA,  YELLOW   FEVER  95 

germ  develops ;  and  that  by  the  mosquito  it  is  injected 
with  the  saliva  as  an  inoculation  into  fresh  victims  during 
the  bite  or  sucking  of  the  animal.  Dog-bite  and  accom- 
panying hydrophobic  inoculations  also  plainly  belong  in 
this  class  of  wound  diseases. 

The  researches  of  Laveran,  Manson,  Ross,  Celli  and 
others  upon  malaria,  and  mosquitoes  as  hosts  of  the  malaria 
parasite,  form  one  of  the  most  brilliant  and  instructive 
chapters  in  the  history  of  sanitary  science  and  experi- 
mental medicine.  The  parasite,  which  infects  the  red 
blood-corpuscles  of  its  victim,  had  been  recognized  for 
several  years,  but  nothing  whatever  was  known  of  its  life 
outside  the  animal  body  or  the  method  of  its  distribution 
until  it  was  discovered  that  the  female  of  at  least  one 
species  of  mosquito  (Anopheles}  is  capable  of  acting  as  an 
effective  vehicle  of  the  micro-parasites  (hsematozoa). 

Further  discoveries  have  shown  that  the  Anopheles  must 
itself  become  inoculated  by  sucking  the  blood  of  a  malarial 
animal ;  that  the  parasites  undergo  an  important  part  of 
their  development  within  the  body  of  the  mosquito  (which 
is  therefore  a  host  as  well  as  a  vehicle  of  the  microbes) ; 
and  that  they  are  conveyed  to  animals  bitten  by  the  mos- 
quito with  the  salivary  poison  injected  during  the  bite. 
The  mosquito,  in  short,  is  an  intermediary  host,  precisely 
as  is  the  hog  in  the  life-cycle  of  Tania,  the  pork  tape- 
worm. The  practical  importance  of  these  discoveries  is 
immense,  for  it  has  already  been  established  by  experi- 
ment that  man  may  live  in  "  malarious  "  districts  with  no 
risk  of  contracting  malaria  provided  pains  are  taken  to 
avoid  absolutely  all  mosquito-bites ;  and  on  the  other  hand, 
it  has  been  shown  that  mosquitoes  that  have  bitten  mala- 
rial subjects  may  readily  transmit  the  disease  by  their  bites, 
and  infect  fresh  victims  even  in  regions  hitherto  abso- 
lutely free  from  malaria. 

More  recently  still  evidence  seemingly  conclusive  has 
been  obtained  —  at  great  personal  risk,  and  with  admirable 


96  ON   INFECTION   AND   CONTAGION 

courage  —  by  American  investigators  in  Cuba  that  yellow 
fever  is  similarly  transmissible  by  mosquitoes,  and  not 
readily,  if  at  all,  by  infected  bedding  or  other  lifeless 
materials. 

Flies  have  of  recent  years  come  to  be  regarded  as  ready 
vehicles  of  infection,  and  especially  of  typhoid  fever. 
Lime  scattered  over  excrements  in  privies  has  been  ob- 
served on  the  feet  and  legs  of  flies  running  over  food  set 
out  for  eating  upon  tables  in  the  neighborhood,  and  if 
lime  can  be  thus  carried,  there  is  no  reason  why  microbes 
also  may  not  be  carried  to  food  or  drink.  It  is  also  prob- 
able that  the  bites  of  flies  may  convey  infection,  although 
this  has  not  yet  been  established.  It  is  believed,  however, 
by  experts  that  one  of  the  principal  sources  of  typhoid 
fever  in  army  camps  is  the  infection  of  food  by  flies  acting 
as  vehicles  of  the  microbic  infection. 

Those  who  would  pursue  these  subjects  further  are  re- 
ferred to  the  following  works :  Celli,  "  Malaria  according 
to  the  New  Researches  "  (English  translation  by  Eyre  and 
an  Introduction  by  Dr.  Patrick  Manson),  Longmans,  Green 
&  Co.,  1900;  Howard,  L.  O.  "  Mosquitoes  :  How  they  Live, 
How  they  carry  Disease,"  etc.,  New  York  (McClure),  1901. 

§  5. — Infection  by  Way  of  the  Alimentary   Canal,  Lungs 
and  the  Genito-urinary  Tracts 

The  alimentary  canal  being  in  free  connection  with  the 
environment  and  really  a  portion  of  it,  is  naturally  subject 
to  invasion  from  various  sources  by  various  micro-organ- 
isms and  similar  extraneous  matters ;  and  the  same  thing  is 
true  of  lungs  and  genito-urinary  tracts,  though  perhaps  in 
less  degree.  The  alimentary  canal,  moreover,  is  ordinarily 
well  stocked  with  food  materials  for  micro-organisms ;  and 
although  the  gastric  juice  probably  exerts  an  unfavorable 
influence  upon  them,  it  may  be  said  that,  on  the  whole,  the 
warm  and  well-fed  alimentary  canal  affords  an  excellent 


INFECTION   IN   DIPHTHERIA  AND   CHOLERA        97 

breeding-ground  for  certain  bacteria.  But  if  bacteria  mul- 
tiply enormously  in  the  alimentary  canal,  they  do  so  at  the 
expense  of  materials  found  therein,  and  in  the  course  of 
their  multiplication  must  produce  various  substances  of  the 
nature  either  of  by-products  or  excreta ;  and  some  of  these 
may  conceivably  be  harmful  either  to  the  guardian  epithelia 
lining  the  alimentary  canal  or  to  the  tissues  in  general,  if 
once  they  are  absorbed  and  distributed  by  the  circulation. 
Similarly,  micro-organisms  grow  freely  within  the  genital 
tracts,  and  feeding  upon  the  exudations  or  secretions  there 
found  may  multiply  enormously,  with  the  consequent  pro- 
duction of  deleterious  substances  which  shall  damage 
either  the  lining  epithelia  or,  when  absorbed,  other  tissues 
of  the  body,  near  or  remote.  Moreover,  in  both  these 
cases  the  paralysis  or  destruction  of  the  guardian  epithelia 
may  produce  actual  solution  of  continuity,  which  shall 
allow  either  the  micro-organisms  in  question  or  their  poi- 
sonous products  to  find  ready  entrance  into  the  body 
proper. 

There  is  reason  to  believe  that  the  bacillus  of  diphtheria, 
for  example,  works  precisely  in  this  way.  Finding  lodg- 
ment upon  the  tissues  of  the  throat,  it  proceeds  to  grow  and 
multiply  upon  the  normal  exudations  and  the  food  materials 
there  present,  and  in  the  course  of  its  vital  activity  pro- 
duces somehow  some  of  that  poisonous  substance  which  is 
now  well  known  as  the  "  toxin  "  of  diphtheria.  This  first 
paralyses  or  otherwise  interferes  with  the  normal  activity  of 
the  cells  lining  the  throat  in  its  immediate  vicinity,  where- 
upon, these  cells  failing  to  do  their  duty,  an  abnormal  exu- 
dation of  lymph  takes  place,  and  this,  coagulating,  produces 
the  well-known  "  white  patches  "  so  common  in  "  the  diph- 
theritic throat."  At  the  same  time  a  powerful  poison,  the 
toxin,  is  being  absorbed  into  the  general  circulation,  and 
causes  those  general  or  constitutional  symptoms  which  are 
characteristic  of  the  disease. 

In  the  case  of  Asiatic  cholera,  there  appears  to  be  first 


98  ON  INFECTION  AND  CONTAGION 

an  invasion  and  then  a  genuine  and  extensive  fermentation 
of  the  contents  of  the  alimentary  canal,  with  an  enormous 
multiplication  of  the  micro-organisms  concerned,  so  that 
these  can  readily  be  detected  in  large  numbers  in  the 
bowel  discharges.  At  the  same  time  the  characteristic 
poison  or  toxin  of  Asiatic  cholera  is  supposed  to  be  liber- 
ated, and  its  absorption  through  the  walls  of  the  alimentary 
canal  is  supposed  to  give  rise  to  constitutional  symptoms 
characteristic  of  the  disease  and  indicative  of  profound 
disturbance  of  the  body  proper,  such  as  vomiting,  fever, 
sweating  and  delirium.  In  these  cases,  as  will  be  observed, 
it  is  not  the  germs  themselves,  at  least  in  the  first  place, 
which  penetrate  into  and  ferment  the  body  itself.  It  is 
rather  by  attacking  the  frontier,  there  and  then  setting  up 
their  own  peculiar  fermentations,  and  producing  poisons 
which  are  easily  absorbed,  that  these  micro-organisms 
first  do  their  harm  and  open  the  way  for  themselves  or 
other  germs  to  enter  into  the  body  proper.  Nevertheless 
the  process,  even  from  the  very  start,  is  one  of  fermenta- 
tion, directly  affecting  either  the  body  wall  or  materials, 
such  as  partially  digested  food  or  secretions,  closely  con- 
nected with  and  for  the  time  being  practically  a  part  of  it. 
(Cf.  §  3,  P-  92.) 

§  6.  —  The  Physiological  Defences  of  the  Living  Body. 
Vital  Resistance  and  Susceptibility  once  more 

The  term  "  vital  resistance  "  has  been  much  used  in  the  last 
few  sections,  coupled  with  the  statement  that  its  exact  sig- 
nificance is  unknown.  It  is  unnecessary  to  argue  again  at 
this  point  that  there  is  such  a  thing  as  vital  resistance,  or 
that  it  varies  largely  from  time  to  time.  The  experience 
and  observation  of  everyday  life  abundantly  testify  to  these 
facts.  Who  has  not  witnessed,  for  example,  that  robust 
and  abounding  health  which  enables  some  persons  to  live 
happily  and  carelessly  in  poverty,  filth,  and  squalor,  while 


INFECTION   THROUGH   TOXIN-ABSORPTION         99 

others,  surrounded  by  every  comfort  and  protection,  perish 
on  the  least  provocation  ?  Again,  who  has  not,  even  in 
himself,  known  times  when  almost  anything  might  be  done 
with  impunity,  and  other  times  when  the  least  exposure  or 
other  unfavorable  condition  led  to  indisposition  or  illness  ? 
Who  has  not  remarked  over  and  over  again  the  immu- 
nity of  youth,  the  fragility  of  age  ?  In  no  other  way  than 
by  recognizing  differences  in  resistance  to  unfavorable 
environments  can  these  anomalies  be  explained,  and  the 
term  "  vital  resistance  "  well  sums  up  and  describes  facts 
established  by  the  long  and  accumulated  experience  of  the 
race.  It  describes  the  facts,  but,  as  so  often  happens  with 
terms  applied  to  human  experience,  it  does  not  explain 
them.  Sanitary  science,  however,  gladly  accepting  and 
using  the  terms  "  vital  resistance  "  and  "  susceptibility,"  — 
the  latter  being  the  converse  of  the  former,  —  seeks  to  go 
further  and  learn,  if  possible,  the  causes  of  these  condi- 
tions, and  the  processes  by  which  they  are  reached.  It 
must  be  frankly  admitted  that  thus  far  the  search  has  not 
been  wholly  successful,  and  yet  something  has  certainly 
been  done,  at  least  toward  making  things  clearer  and  more 
comprehensible.  (Cf.  pp.  74-85.) 

It  is  easy  to  see  that  "  vital  resistance  "  must  be  largely 
constitutional.  It  must  depend  either  upon  the  materials 
of  which  the  body  is  built  or  on  the  way  in  which  these 
are  put  together,  or,  more  likely,  upon  both.  In  order  to 
resist  the  attacks  of  micro-organisms  upon  epithelial  sur- 
faces ;  or  to  overcome  them  on  their  arrival  if  thrust  in  by 
force  through  the  skin,  as  happens  in  wounds ;  or  in  order 
to  neutralize  their  poisons  (toxins)  if  these  succeed  in  break- 
ing down  and  passing  through  the  epithelia  or  the  skin, 
mechanical  and  chemical  defences  within  the  body  —  phys- 
iological defences  —  would  seem  to  be  most  useful ;  and 
it  is  therefore  interesting  to  find,  as  we  do,  that  the  modern 
theories  of  "vital  resistance"  (which  in  its  most  perfect 
form  is  now  called  "  immunity")  proceed  along  these  lines. 


100  ON   INFECTION   AND  CONTAGION 

A  little  reflection  will  show  that  micro-organisms  on 
entering  the  body  or  any  of  its  passages  are  immediately 
subjected  to  a  peculiar  environment,  which  for  many 
species  must  be  highly  unfavorable.  This  may  be  said  to 
be  the  simplest  of  the  physiological  defences.  The  first 
of  these  met  with  may  be  the  gastric  juice,  which  for  many 
microbes  is  highly  unfavorable  on  account  of  its  acidity. 
The  comparative  immunity  of  plants  to  bacterial  diseases 
and  their  relative  susceptibility  to  the  attacks  of  fungi  has 
been  accounted  for  in  part  on  the  ground  of  the  greater 
acidity  of  their  juices.  Those  microbes  known  as  "  disease 
germs,"  on  the  other  hand,  must  be  supposed  to  find  the 
new  conditions  more  or  less  favorable ;  more  if  the  patient 
is  susceptible ;  less  if  he  is  endowed  with  considerable  vital 
resistance ;  wholly  unfavorable  only  if  he  is  immune. 

Even  milk,  which  is  well  known  for  its  blandness  and 
as  a  favorable  culture  medium  for  many  bacteria,  being 
literally  crowded  with  certain  species  when  it  is  stale,  has 
been  described  as  "  germicidal," 1  so  that  the  first  and  very 
likely  the  most  important  physiological  defence  of  the  liv- 
ing body  may  be  the  fact  that  merely  as  such  it  furnishes 
an  unfavorable  environment  for  many  invading  organisms. 
The  bodies  of  micro-organisms  perishing  in  the  invaded 
territory,  whether  this  be  local  or  general,  in  the  healthy 
animal  soon  disappear,  and  there  is  reason  to  believe  that 
they  are  removed  by  the  white  corpuscles  of  the  blood  and 
the  lymphatics,  acting  as  scavengers.  Whether  these  de- 
vouring cells  (phagocytes)  are  soldiers  as  well  as  scaven- 
gers, whether  or  not  they  can  kill  as  well  as  devour  invading 
micro-organisms,  is  not  wholly  clear.  The  view  that  they 
can  and  do,  and  that  acquired  immunity  depends  largely 
on  their  training  so  that  they  shall  do  it  successfully 
(MetschnikofFs  theory  of  immunity  by  "  phagocytosis  "), 
while  it  has  developed  many  interesting  facts  (as  stated 

1  "  Ueber  die  Bakterienvernichtenden  Eigenschaften  der  Milch,"  Baum- 
garten's  Jahresbericht  ueber  Mikroorganismen,  VI.  513,  529. 


INTERNAL  DEFENCES  AGAINST   INFECTION      IOI 

above),  seems  somewhat  too  picturesque  and  too  an- 
thropomorphic. It  is  not  much  easier  to  understand 
with  Behring  and  Roux  how  the  cells  of  the  tissues  or  the 
blood  after  one  attack  of  an  infectious  disease,  such  as 
diphtheria,  are  so  "  affected  "  that  they  secrete  regularly 
thereafter  and  in  its  absence  a  chemical  antidote  for  the 
diphtheria  toxin. 

Perhaps  the  truth  is  to  be  found  in  a  combination  of 
these  various  views.  The  physiological  defences  may  very 
likely  consist  in  (i)  the  fact  that  the  living  body  merely  as 
it  stands  offers  to  many  micro-organisms  an  unfavorable  en- 
vironment for  their  normal  development ;  (2)  the  fact  that 
some  microbes  on  entering  are  seized  and  devoured  by 
phagocytes  drawn  to  them  by  chemiotactic  influences ; 
(3)  the  fact  that  over  and  above  the  general  unfavorable- 
ness  of  environment,  immune  animals  possess  somehow, 
either  naturally  or  acquired,  the  faculty  of  subjecting 
special  invaders  or  their  products  (toxins)  to  the  action 
of  special  chemical  substances  (antitoxins)  which  destroy 
their  efficiency. 

It  will  be  observed  that  in  all  these  cases  the  defence 
consists  essentially  in  a  kind  of  internal  or  physiological 
disinfection,  which  whether  real  or  not  is  conceivable 
enough.  But  besides  this  we  have  to  recognize  the  fact 
that  the  living  cells  of  the  epithelia  appear  to  have  a  certain 
power  of  "  selection,"  at  present  not  understood,  Doubtless 
this  is  no  more  mysterious  than,  for  example,  that  power 
of  selection  which  the  absorbents  appear  to  exercise,  or 
that  property  of  the  cells  of  the  stomach  or  intestine  by 
virtue  of  which  they  are  not  digested  by  their  own  juices 
respectively.  The  fact,  however,  remains  at  present  essen- 
tially unexplained. 

§  7.  —  The  Precise  Meaning  of  Contagion 

The  terms  "  infection  "  and  "  contagion  "  as  applied  to 
processes  rather  than  substances  (for  in  the  latter  case 


102  ON  INFECTION  AND  CONTAGION 

they  mean  exactly  the  same  thing)  may  now  be  further 
denned  and  explained.  The  former,  strictly  speaking, 
signifies  "  entrance,"  the  latter  "  contact."  Though  often 
used  as  if  synonymous,  they  are  not  best  so  used.  Infection 
is  the  broader  and  larger  term,  and  includes  contagion.  It 
signifies  simply  the  entrance  or  "  making  into  "  the  body  of 
harmful  material.  This  may  be  either  living  or  lifeless, 
but  the  term  is  generally  applied  to  the  entrance  or  mak- 
ing in  of  living  organisms  by  any  method  or  avenue  what- 
soever. Contagion,  on  the  other  hand,  is  only  a  particular 
kind  of  infection  of  living  organisms  or  microbes  hi  which 
the  infecting  substance  is  transferred  from  source  to  sub- 
ject by  direct  contact,  as,  for  example,  when  the  contagion 
or  infection  of  small-pox  is  derived  by  the  victim  directly 
from  contact  with  a  preceding  case.  Infection  is  well 
illustrated  by  cases  of  typhoid  fever  or  Asiatic  cholera  in 
which  the  bowel  discharges  of  a  person,  A,  find  access  to 
water  or  milk  and  are  consumed  with  food  or  drink  by 
another  person,  B.  In  this  case  B  may  never  have  seen, 
or  heard  of,  or  been  anywhere  near,  A,  and  there  may  have 
been  no  contact  whatever  between  them.  In  a  word,  con- 
tagion is  direct,  immediate  —  and  generally  personal  — 
infection,  while  other  forms  of  infection  are  more  or  less 
roundabout  and  indirect.  Contagion  operates,  neverthe- 
less, in  precisely  the  same  way  as  infection.  In  all  cases 
whether  of  infection  or  contagion  there  must  be  somehow 
a  transfer  of  infectious  material  more  or  less  directly  from 
an  antecedent  or  primary  case  as  a  cause,  to  a  consequent 
or  secondary  case  as  an  effect ;  and  it  matters  not,  except 
as  to  details,  whether  the  infectious  material  is  derived 
immediately  from  the  antecedent  case  by  actual  contact 
with  it,  or  after  the  lapse  of  a  long  time  and  in  obscure 
and  roundabout  ways.  Both  phenomena  belong  in  the 
same  category,  though  the  more  obvious  is  called  "  con- 
tagion" and  the  less  obvious  "infection."  It  would  be 
better  to  drop  altogether  the  term  "  contagion,"  and  to 


INFECTION    VS.   CONTAGION  103 

apply  to  all  these  cases  the  simple  and  accurate  term 
"  infection,"  l  which,  if  we  neglect  the  idea  of  entrance  by 
force,  has  almost  exactly  the  same  significance  as  "inva- 
sion," and  corresponds  precisely  to  the  popular  term  often 
applied  to  infectious  disease,  namely,  an  "  attack." 

§  8.  —  Man   and  Other  Animals  the  Principal  Primary 
Sources  of  Infection 

We  have  now  considered  somewhat  briefly  the  portals  of 
entrance  of  infectious  materials  into  the  body  proper,  and 
have  hinted  at  some  of  the  vehicles  of  infection.  Before 
dwelling  long  upon  these  it  will  be  well  to  consider  the 
original  sources  of  infectious  matenals  in  the  environment. 
Once  we  have  determined  the  sources  of  infections,  it  will 
be  comparatively  easy  to  discover  the  avenues  of  communi- 
cation and  the  vehicles  by  which  they  travel. 

It  was  formerly  supposed  that  the  earth  and  various  other 
non-living  materials  were  prolific  original  sources  of  infec- 
tious disease,  or  in  other  words,  that  the  germs  of  disease 
not  only  exist  but  thrive  and  multiply  in  the  earth.  It  was 
thought,  for  example,  and  is  still  held  by  some,  that  the 
micro-organism  of  typhoid  fever  passes  a  portion  of  its  life 
and  undergoes  a  necessary  portion  of  its  development  in  the 
soil,  especially  in  filthy  soil,  and  similar  ideas  were  held  in 
regard  to  other  infectious  diseases.  Doubtless  the  reason 
for  this  opinion  was  to  be  found  in  the  fact  that  certain 
animal  and  vegetable  parasites  had  been  known  for  a  long 
time  to  spend  one  portion  of  their  lives  in  or  upon  some 
plant  or  animal  other  than,  and  often  lower  than,  their 
most  conspicuous  host.  This  is  true  of  the  tapeworm,  the 
TricJiina,  the  blight  of  barberries,  and  many  other  para- 

1  Much  confusion  in  the  use  of  these  and  related  terms  exists  in  the  works 
of  the  earlier  authors.  Even  Dr.  Farr  (/.r.)  refers  to  "  diseases  propagated 
either  by  inoculation  and  contact  (contagion)  or  by  inhalation  (infection)," 
and  says  "  miasms  produce  diseases  like  ague,  without  being  propagated  by 
contagion." 


104  ON  INFECTION  AND  CONTAGION 

sites.  The  progress  of  inquiry,  however,  has  not  confirmed 
these  ideas,  except  in  special  cases  (such  as  that  of  tetanus, 
p.  94),  for  the  ordinary  infectious  diseases.  It  has  been 
said  that  some  still  hold  to  the  idea  in  the  case  of  typhoid 
fever;  but  the  author  believes,  after  a  very  considerable 
investigation  of  the  question,  and  personal  studies  of  epi- 
demics which  he  has  had  somewhat  unusual  opportuni- 
ties to  witness,  that  this  idea  is  not  sound,  and  that  every 
case  of  typhoid  fever,  at  least  in  the  latitude  of  New 
England,  arises  rather  directly  from  an  antecedent  case, 
and  in  this  way  only.  It  is,  of  course,  possible  that  in 
other  latitudes,  and  under  conditions  particularly  favora- 
ble, the  typhoid  bacillus  may  grow  outside  the  human 
body.  There  is  no  question  that  under  favorable  condi- 
tions it  can  do  this  in  laboratories ;  but  that  it  does  so  in 
nature  in  temperate  climates,  except  under  very  unusual 
circumstances,  does  not  seem  to  be  indicated  by  the  evi- 
dence at  hand.  It  can  unquestionably  live  for  some  time 
in  nature,  though  apparently  with  diminishing  virulence, 
and  in  diminishing  numbers ;  but  in  northern  latitudes 
and  under  ordinary  conditions  its  prolonged  survival,  and 
especially  its  multiplication  outside  the  body,  must  be 
doubted. 

A  similar  statement  may  be  made  in  the  case  of  many 
infectious  diseases,  and  we  may  safely  say  that  for  the 
most  part  man  and  other  animals  are  the  original  sources 
of  infectious  disease.  But  it  should  always  be  remem- 
bered that  under  tropical  conditions,  if  only  suitable  food 
and  moisture  be  present  and  other  conditions  favorable, 
the  germs  of  infectious  disease  may  live  long  and  actually 
multiply  outside  the  animal  body. 

Since  the  above  paragraphs  were  written  the  amazing 
revelations  of  the  r61e  played  by  mosquitoes  in  the  convey- 
ance and  the  development  of  malaria  have  been  made. 
From  these  it  appears  that  here  also  a  disease  long  associ- 
ated with  swamps  and  mysterious  "  miasms  "  has  its  sources 


SOURCES   AND  PRIME-MOVERS   OF  INFECTION      io$ 

only  in  animal  bodies,  for  the  malarial  parasite  comes  from 
the  bodies  of  men  and  mosquitoes,  which  thus  appear  to 
be  the  only  original  sources  of  infection. 

§  9.  —  Man  and  Other  Animals,  and  especially  their  Ex- 
creta, the  Principal  Primary  Vehicles  or  Prime-movers 
of  Infection 

If  it  be  true  that  man  and  other  animals  are  the  principal 
original  sources  of  infection,  it  must  follow  as  a  matter  of 
course  that  their  excreta  are  its  principal  original  vehicles ; 
for  the  excreta  represent  the  output  of  the  organism,  its 
contribution  to  the  environment.  Physiology  teaches  that 
the  material  output  of  the  animal  body  consists  of  dis- 
charges from  the  alimentary  and  genito-urinary  passages 
and  from  the  skin,  —  the  nose  and  lungs  being  regarded 
as  branches  of  the  alimentary  apparatus,  —  and  accord- 
ingly it  is  these  discharges  which  must  be  the  principal 
original  vehicles  of  infectious  disease  from  its  place  of 
origin  to  the  environment.  Diseases  have,  in  the  past, 
often  been  roughly  classified  according  to  their  place 
of  origin  and  the  vehicles  by  which  they  are  con- 
veyed. An  important  class  of  infectious  maladies  known 
as  "  diarrhoeal "  diseases  is  directly  attributed  to  infections 
from  the  bowel  discharges.  Typhoid  fever,  Asiatic  cholera, 
dysentery,  diarrhoea,  and  cholera  infantum  are  the  most 
important  members  of  this  class.  Of  equal  or  even  greater 
importance  are  those  diseases  known  as  "eruptive"  dis- 
eases, which  are  readily  scattered  from  seedings  of  the  shed- 
off  skin.  In  these  cases,  pustules  form  on  the  skin  and, 
opening  to  the  exterior,  discharge  their  secretions  there. 
To  this  class  belong  some  of  the  worst  diseases  that  afflict 
the  human  race,  such  as  small-pox,  typhus  fever,  scarlet 
fever,  measles,  chicken-pox  and  many  more.  Since  the 
infectious  material  is  in  this  case  poured  out  upon  the  sur- 
face of  the  body,  it  is  readily  transferred  by  direct  contact 
to  the  fingers,  and  thereby  to  the  mouths  or,  when  dried, 


106  ON  INFECTION  AND  CONTAGION 

by  the  wind,  to  the  noses  and  lungs  of  other  persons. 
Hence,  the  term  "  contagious  "  diseases,  especially  applied 
to  this  group.  Again,  a  certain  number  of  diseases 
affecting  the  mouth,  throat,  or  lungs  may  be  conveyed  by 
means  of  the  sputum  or  saliva  thrown  out  of  the  mouth 
and  eventually  finding  its  way  either  when  dried,  pulver- 
ized and  blown  about  by  the  wind,  or  through  the  agency 
of  food  contaminations,  to  other  susceptible  persons.  In 
this  group  would  naturally  be  found  diphtheria  and  pul- 
monary tuberculosis. 

The  other  excreta,  such  as  the  urine  and  the  breath,  as 
well  as  the  sweat,  are  not  usually  charged  to  the  same 
extent  with  the  carriage  of  disease.  The  expired  air  from 
the  lungs,  formerly  so  much  dreaded  by  those  who 
watched  at  the  bedside,  appears  according  to  the  careful 
investigations  of  bacteriologists  to  be  the  least  dangerous 
of  all  the  excreta,  being  practically  germ-free.  The  rea- 
son for  this  is  that  the  moist,  spongy  lungs  act  as  an  effi- 
cient filter,  and  not  only  refuse  to  yield  up  micro-organisms 
to  the  expired  air,  but  even  detain  organisms  arriving  in 
the  inspired  air,  so  that  the  outgoing  breath  of  a  patient  is 
from  the  bacteriological  point  of  view  actually  purer  than 
the  inspired  air.  Recent  researches,  on  the  other  hand, 
have  shown  that  the  urine  may  be  a  ready  vehicle  of  the 
microbes  of  typhoid,  and  very  likely  of  other,  fevers. 

It  is  interesting  to  note,  also,  that  the  malarial  parasite 
passes  from  mosquito  to  man  with  an  excretion,  the  saliva. 
From  man  to  mosquito  it  does  not  pass  in  this  way,  but 
rather  as  a  contamination  of  stolen  food,  the  sucked  blood 
being  itself  infected. 

§  10. — Earth,  Air,    Water  and  Animals  the  Principal 
Secondary   Vehicles  of  Infectious  Disease 

But  if  the  excreta  are  the  principal  original  vehicles  of 
infection,  they  are  by  no  means  the  only  vehicles,  for  they 


AIR,  FOOD  AND   DRINK  AS  VEHICLES  107 

may  readily  mingle  with  and  transfer  their  burden  of  in- 
fection to  almost  any  substance  in  the  environment. 
From  the  skin  the  surrounding  air  may  first  become 
infected  and  then  move  on,  laden  with  disease,  so  that 
disease — or  rather  its  germs — may  literally  be  borne  on 
"the  wings  of  the  wind."  Likewise,  sputum  from  the 
mouth,  or  discharges  from  the  bowels,  may  be  impercepti- 
bly mingled  with  a  stream,  so  that  a  cup  of  cold  water  — 
the  time-honored  symbol  of  purity  and  charity  —  may  con- 
tain unseen  and  unsuspected  the  germs  of  deadly  or  dis- 
gusting diseases.  Or,  again,  the  earth  impregnated  with 
human  excreta  may  be  dried  and  pulverized,  and,  as  dust 
infecting  human  throats,  become  the  vehicle  of  diseases 
such  as  diphtheria  or  tuberculosis.  Clearly,  if  animal  life 
is  the  principal  source  of  infection,  and  the  excreta  of  ani- 
mals are  its  principal  vehicles,  these,  being  some  solid, 
some  liquid  and  some  gaseous,  are  only  too  likely  to  find 
kindred  substances  in  the  environment  with  which  they 
can  mingle,  and  to  which  they  can  convey  a  portion  at 
least  of  their  burden  of  infection. 

We  have  already  seen  how  insects  may  become  the 
bearers  of  infection,  and  we  may  now  turn,  in  the  follow- 
ing chapters,  to  a  detailed  consideration  of  several  other  of 
the  most  important  and  most  common  vehicles  of  infec- 
tion, namely,  dirt,  dust,  air,  sewage,  water,  ice,  milk,  raw 
foods  (such  as  oysters  and  salads)  and  the  like,  and  the 
ways  in  which  these  can  be  protected  or  purified. 


CHAPTER  VI 

ON  DIRT  AND  DISEASE.  THE  LIVING  EARTH.  DIRT,  DUST 
AND  AIR  AS  VEHICLES  OF  INFECTION.  FILTH,  FILTH  DIS- 
EASES AND  THE  PHILOSOPHY  OF  CLEANNESS 

u  Undeanness  must  ...  be  reckoned  as  the  deadliest  of  our  present 
removable  causes  of  disease."  —  SIR  JOHN  SIMON. 

"  Cleanliness  covers  the  whole  field  of  sanitary  labor.  It  is  the  be- 
ginning and  the  end."  —  DR.  B.  W.  RICHARDSON. 

THE  experience  of  the  race  has  shown  that  one  of  the 
most  effective  vehicles  of  disease  is  dirt.  The  word  "  dirt " 
appears  to  be  derived  from  an  old  Saxon  word  drit,  mean- 
ing excrement ;  but  the  modern  form  of  the  word  "  dirt "  has 
taken  on  a  more  extended  and  less  definite  meaning.  As 
ordinarily  used  it  may  be  the  synonym  of  dust,  soil,  filth 
or  almost  any  form  of  uncleanness,  whether  such  unclean- 
ness  imply  the  presence  of  infection  or  only  that  of  pollu- 
tion. Still  it  can  hardly  be  denied  that  even  at  present 
the  word  "  dirt "  signifies  something  distinctly  more  filthy 
than  do  the  words  "  earth,"  "  soil "  or  "  dust."  It  is  easy  to 
see  in  the  origin  of  the  word  the  reason  for  this,  and  after 
what  has  been  said  in  the  preceding  chapters  concerning 
the  primary  sources  of  infection  and  the  efficiency  of  ex- 
crement as  a  vehicle,  no  surprise  need  be  felt  that  dirt 
is  regarded  with  suspicion  by  all  intelligent  and  well- 
informed  persons. 

§  I .  —  Clean  Earth  and  Infections  Dirt 

Unquestionably  the  general  fear  of  dirt  among  the  in- 
telligent is  not  in  all  cases  discriminating.  There  may  be, 

108 


DEFINITIONS  109 

and  probably  are,  forms  of  dirt  which  carry  with  them 
very  little  of  danger,  and  a  certain  recognition  of  this  fact 
is  shown  in  such  expressions  as  "  good  clean  earth."  It 
appears  to  be  true  that  while  it  is  the  earth  that  is  most 
often  associated  with  the  idea  of  dirt,  it  is  ordinarily  only 
the  surface  of  the  earth  which  is  thus  looked  upon  with 
suspicion  and  aversion.  One  reason  for  this  probably  is 
that  the  surface  or  loamy  layers  of  the  soil  are  not  infre- 
quently sticky  and  suggestive  of  organic  matters,  while 
the  subsoil  directly  below  the  loam  layer  is  generally  more 
obviously  mineral  in  its  character  and  often  clean,  i.e.  not 
sticky  or  "  dirty."  As  a  matter  of  fact  the  loamy  layer  so 
called  is,  in  truth,  richer  in  organic  matters,  and  besides 
often  containing  innumerable  earthworms  is  crowded  with 
the  bodies  of  micro-organisms.  The  earthworms  by  their 
ploughing  actions,  which  Darwin  has  so  admirably  worked 
out,  are  constantly  turning  over  the  upper  layers  of  the 
earth,  carrying  from  the  surface  into  the  lower  strata 
organic  matters,  and  from  below  to  the  surface  the  more 
mineral  subsoil.  It  follows,  therefore,  that  not  only  is  the 
surface  of  the  earth  contaminated  by  excrement  of  various 
kinds  that  falls  upon  it,  but  also,  through  the  agency  of 
earthworms,  a  considerable  portion  of  the  earth  just  below 
the  surface,  and  especially,  no  doubt,  the  loamy  layer 
already  referred  to. 

Accordingly,  if  we  desire  to  define  and  classify  the  terms 
already  used,  we  shall  say  that  earth,  broadly  speaking  and 
for  the  most  part,  is  essentially  mineral  in  character  and 
clean  in  condition  because  free  from  any  considerable 
amount  of  organic  matter.  It  is  also,  therefore,  ordinarily 
free  from  infection  —  uninfected  as  well  as  unpolluted. 
Soil,  i.e.  the  surface  layer  of  the  earth,  may  be  clean, 
and  may  be  and  ordinarily  is  fairly  free  from  infectious 
materials,  but  inasmuch  as  it  is  exposed  to  contamination 
by  dirt,  i.e.  excrement,  and  is  being  continually  worked 
over  by  earthworms,  it  may  be  and  usually  is  more  or  less 


1 10     ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

polluted  or  contaminated  with  organic  matter.  It  may  or 
may  not  be  infected.  Dirt  in  the  original  and  most  exact 
sense  is  simply  excrement,  but  in  the  more  ordinary  use  of 
the  word  is  soil,  i.e.  the  surface  layer  of  the  earth,  which 
may  or  may  not  contain  infectious  materials. 

§  2.  —  The  Living  Earth 

It  is  one  of  the  most  marvellous  revelations  of  bacteri- 
ology that  the  earth,  long  regarded  as  the  type  of  lifeless- 
ness,  is  in  fact,  at  least  in  its  uppermost  layers,  teeming  with 
life.  Not  only  do  many  mammals,  birds,  reptiles,  insects, 
and  worms  have  their  homes  in  the  earth,  but,  as  bacteri- 
ology teaches,  also  vast  hosts  of  micro-organisms,  more 
abundant  by  far  than  the  grains  of  sand  upon  which  they 
dwell.  A  single  gram  of  garden  soil  may  contain  millions 
of  micro-organisms,  and  much  of  the  softness  and  sticki- 
ness of  moist  loam  is  probably  due  to  the  presence  of  such 
numbers  of  soft  protoplasmic  bodies.  Thus  it  has  come 
to  pass  that  we  are  no  longer  at  liberty  to  speak  or  think 
of  the  earth,  at  least  in  its  upper  layers,  as  dead  and 
essentially  mineral,  but  must  regard  it  instead  as  highly 
organic  and  quivering  with  life. 

§  3.  —  Earth  as  a  Vehicle  of  Disease.     Tetamis  or  Lockjaw 

once  More 

The  earth  is  not  only  rich  in  germs,  but  may  contain 
among  these  some  that  are  pathogenic  or  disease-produc- 
ing. Reference  has  already  been  made  to  tetanus  as 
caused  by  specific  microbes  found  in  the  soil  (pp.- 94,  104), 
and  these  are  especially  interesting,  inasmuch  as  they 
appear  to  lead  regularly  a  saprophytic  rather  than  a  para- 
sitic life.  In  this  respect  we  have  reason  to  suppose  that 
they  (and  a  few  others)  differ  from  most  pathogenic 
microbes,  which  fortunately  do  not,  under  ordinary  con- 


THE   LIVING   EARTH  III 

ditions,  appear  to  thrive  (though  they  may  continue  to  live 
for  a  long  time)  outside  the  plant  or  animal  body. 

§  4.  —  Dust  and  Disease 

Dust  is  pulverized  soil  or  pulverized  dirt,  and  only  rarely 
pulverized  and  pure  earth.  It  is  therefore,  as  a  rule,  rich 
in  bacteria,  and  may  or  may  not  contain  infectious  disease 
germs.  Inasmuch  as  it  is  the  surface  of  the  earth  which 
is  ordinarily  dried,  pulverized  and  lifted  into  the  air,  it  is 
easy  to  see  that  excrement  of  any  kind,  deposited  upon  the 
soil,  sputum  and  other  organic  matters  cast  off  by  ani- 
mal bodies,  —  such  as  scales  from  the  skin,  bits  of  hair, 
dandruff  and  the  like,  —  as  well  as  the  possible  combina- 
tion of  all  these  things  with  dirty  water  to  make  sewage, 
may  when  dried  on  the  surface  of  the  earth  be  also  readily 
pulverized  and  lifted  into  the  air  as  fine  particles  or  motes 
of  dust.  At  first  sight,  dust  of  this  character  might  be 
supposed  to  be  necessarily  dangerous  and  even  deadly, 
and  there  is  very  little  doubt  that  infectious  diseases  are 
in  fact  frequently  transmitted  by  dust  which  serves  as  a 
vehicle;  but,  on  the  other  hand,  it  should  not  be  for- 
gotten that  there  are  certain  compensating  circumstances 
which  tend  to  diminish  the  dangers  of  disease  from  this 
source.  The  unfavorable  conditions  to  which  micro-organ- 
isms are  exposed  in  dust,  namely,  desiccation,  possible  ger- 
micidal  action  of  light,  unfavorable  temperatures  and  the 
like,  undoubtedly  destroy  many  of  them  and  weaken  oth- 
ers, but,  in  spite  of  these  various  fortunate  conditions,  it 
still  remains  true  that  dust  must  always  be  regarded  by 
the  sanitarian  as  dangerous,  not  only  because  of  the 
mechanical  irritation  of  the  delicate  mucous  membranes 
of  the  throat  and  other  respiratory  passages  caused  by  the 
inorganic  particles  of  which  it  is  largely  composed,  but 
also  because  of  the  possibility  of  its  containing  virulent 
disease  germs,  such  as  those  of  tuberculosis  or  diphtheria 


112     ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

from  the  sputum  of  persons  affected  with  these  maladies  ; 
as  well  as  those  of  small-pox,  scarlet  fever,  measles  and 
the  like,  from  the  skin-scales  of  victims  of  these  diseases ; 
and,  to  a  less  extent  perhaps,  the  germs  of  typhoid  fever 
and  other  diarrhceal  diseases  from  the  pulverized  excreta 
of  walking  cases,  or  from  night  soil  spread  upon  fields  for 
manure  and  afterward  dried  and  lifted  into  the  air  by 
winds  during  the  operations  of  hoeing,  harrowing,  plough- 
ing and  the  like.1 


§  5. —  The  Atmosphere  as  a   Vehicle  of  Disease ;  Ancient 
and  Modern  Theories 

From  the  earliest  times  the  atmosphere  has  been  regarded 
with  suspicion  as  a  vehicle  of  disease.  Miasms,  pestilential 
vapors  and  various  mysterious  and  unseen  influences  have 
been  regarded  as  readily  conveyed  by  the  atmosphere,  and 
obscure  or  occult  effects  not  comprehended  or  else  mis- 
understood have  been  attributed  naturally  enough  to  the 
omnipresent  and  always-moving  atmosphere.  It  is  one  of 
the  merits  of  the  germ  theory  of  infectious  disease  that  it 
enables  us  to  comprehend  much  more  clearly  than  ever 
before  the  true  nature  of  these  supposed  atmospheric  influ- 
ences. From  what  has  just  been  said  in  the  last  paragraph, 
it  is  easy  to  see  that  the  atmosphere  may  under  certain  cir- 
cumstances be  a  ready  carrier  of'infectious  disease  simply 
by  serving  as  the  vehicle  for  the  floating  organic  matters 
and  living  particles  which  are  lifted  into  it  from  the  surface 
of  the  earth  or  from  human  bodies.  Doubtless  it  is  with 
these  very  much  as  it  is  with  the  l)irds  of  the  air  or  the 
flying  fish  of  the  sea,  which,  caught  up  or  springing  from 
the  earth  or  the  sea,  may  for  a  longer  or  shorter  time  float, 
fly  or  swim  in  the  atmosphere,  but  which  after  all  belong 

1  Those  who  wish  to  pursue  this  subject  further  may  consult  with  advantage 
Tyndall's  "  Essays  on  the  Floating  Matter  of  the  Air,"  New  York  (Appleton), 
and  Prudden's  "Dust  and  its  Dangers,"  New  York  (Putnams). 


THE  ATMOSPHERE   AND   DISEASE  113 

to  the  earth  and  sooner  or  later  return  to  it.  It  must  not, 
however,  be  forgotten  that  the  germs  of  the  commoner  con- 
tagious diseases,  and  especially  of  those  known  as  "  erup- 
tive," in  which  "  peeling  "  of  the  skin  occurs,  may  be  and 
probably  are  often  disseminated  through  the  atmosphere, 
and  that  so  much  of  truth  existed  in  the  primitive  ideas  of 
mankind. 

§  6. — Microbes  of  the  Air 

The  number  of  microbes  in  the  atmosphere  varies 
greatly.1  In  a  dust-storm  five  feet  above  the  surface  of  a 
macadamized  street  the  author  and  one  of  his  pupils,  Mr. 
(now  Dr.)  John  A.  Rockwell,  Jr.,  detected  in  ten  litres 
of  air  two  hundred  thousand  micro-organisms.  Quiet  air 
is  usually  relatively  free  from  them  (sewer  air,  for  exam- 
ple, being  often  nearly  or  quite  destitute  of  microbes),  and 
the  same  is  true  of  the  atmosphere  at  high  altitudes  and  in 
mid  ocean.  Even  the  expired  air  of  the  human  lungs  is 
quite  free  from  germs,  a  fact  doubtless  due  to  the  spongy 
and  moist  pulmonary  surfaces  which  catch  and  detain  in- 
coming microbes  and  a  phenomenon  of  great  interest  and 
importance  in  the  theory  of  infection. 

It  is  impossible  to  conceive  of  any  other  source  or  sources 
of  infectious  disease  in  the  atmosphere  than  microbes.'  On 
the  other  hand,  there  is  no  difficulty  in  supposing  that  the 
ground  air,  rising  and  mingling  with  the  ordinary  atmos- 
phere, especially  in  periods  of  low  barometer ;  the  gaseous 
exhalations  of  marshes,  volcanoes,  and  the  like ;  the  results 

1  The  presence  of  microbes  in  the  air  is  easily  demonstrated,  and  their 
number  enumerated,  by  various  methods  described  at  length  in  works  on 
bacteriology.  One  of  the  simplest  methods  is  that  devised  by  the  author  and 
Mr.  (now  Professor)  G.  R.  Tucker.  It  consists  in  filtering  a  known  volume 
of  air  through  fine  sugar  or  sand  —  the  latter  having  been  found  by  experience 
to  be  preferable  —  by  means  of  an  exhausted  cylinder  and  a  glass  tube  of 
special  form,  called  an  aerobioscope,  capable  of  being  converted  at  will  into  a 
"  roll "  tube.  The  micro-organisms  are  held  back  by  the  sand,  and  together 
with  the  latter  are  mixed  with  melted  gelatin  during  the  rolling  process  and 
afterwards  incubated,  cultivated,  enumerated  and  studied. 


1 14    ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

of  decomposition  of  dung-heaps,  filth  and  other  masses  of 
decaying  organic  matter  may,  under  certain  circumstances, 
act  as  unfavorable  environmental  conditions  and  reduce 
the  vital  resistance  to  such  a  point  that  disease,  which 
would  otherwise  have  been  absent,  occurs.  This  simple 
view  probably  includes  all  or  nearly  all  of  the  facts  relat- 
ing to  the  atmosphere,  strictly  so  called,  as  a  source  of 
disease,  and  probably  suggests  the  true  explanation  of 
diseases  supposed  to  be  due  to  miasms,  pestilential  vapors, 
atmospheric  and  telluric  influences,  and  the  like.  Even 
malaria,  which  has  long  been  a  puzzle  to  sanitarians,  is 
apparently  due  not  to  any  peculiar  evil  quality  of  disturb- 
ance of  the  atmosphere,  such  as  the  word  implies,  but 
rather  to  specific  micro-organisms  conveyed  by  the  latter 
either  directly  as  floating  particles,  or  indirectly  through 
insects  or  other  living  agents  of  transmission  moving  in  or 
through  the  air  (see  pp.  94-96).  Malaria  has  often  been 
called  paludism  or  swamp  fever ;  but  if  the  modern  view  is 
correct  it  is  not  swamp  air,  but  swamp  insects  (mosquitoes), 
which  under  favorable  circumstances  transport  the  germs 
of  paludism. 

§  7.  —  Filth  Diseases.      The  Pythogenic  Theory.     Modern 
Views  of  Filth  and  Filth  Diseases 

The  principles  which  have  been  laid  down  in  the  pre- 
ceding chapters  enable  us  to  take  up  with  regard  to  filth 
diseases  a  somewhat  different  view  from  that  held  in  the 
third  quarter  of  the  nineteenth  century.  The  term  "  filth 
diseases "  was  at  that  time  used  with  the  idea  that  filth 
might  be  not  only  a  vehicle,  but  an  actual  breeder  or  gen- 
erator of  infectious  disease.  This  view  even  reached  the 
dignity  of  a  theory  bearing  a  special  name  —  the  "pytho- 
genic  "  theory,  —  which  is  closely  associated  with  the  name 
of  Murchison.  According  to  Murchison,  filth  was  danger- 
ous not  merely  because  it  was  a  vehicle  of  disease,  or  an 


THE   "PYTHOGENIC"  THEORY   OF   DISEASE       115 

unfavorable  condition,  but  also  because  it  was  a  source  of 
disease,  the  supposition  being  either  that  specific  disease 
germs  could  be  generated  de  novo  from  other  germs  in 
filth,  under  favorable  circumstances,  or  that  at  least  germs 
capable  of  producing  disease  found  in  filth  the  conditions 
for  their  more  perfect  development,  some  even  requiring 
residence  for  a  time  in  filth  in  order  to  reach  their  full 
maturity.  In  regard  to  typhoid  fever,  for  example,  it  was 
held  that  the  micro-organisms  of  the  disease  required  a 
stay,  longer  or  shorter,  in  the  earth  or  heaps  of  filth,  and 
only  after  such  a  period  attained  their  natural  and  dan- 
gerous development.  The  older  treatises  on  typhoid  fever 
and  the  older  teaching  often  referred  to  a  residence  in  the 
earth  as  one  phase  in  the  ordinary  development  of  the 
germs  of  typhoid  fever. 

The  pythogenic  theory  requires  some  consideration  at  this  point,  as 
it  lies  at  the  basis  of  much  popular  misconception  of  the  origin  of 
infectious  disease  and,  by  misleading,  causes  a  neglect  of  the  true 
sources  of  disease.  It  was  first  propounded  by  Murchison  in  a  foot- 
note to  a  paper  read  before  the  Royal  Medical  and  Chirurgical  Society 
of  London,  April  27,  1858  (Med.  Chirurg.  Trans.  1858,  p.  221): 
"  In  the  course  of  this  essay  I  shall  bring  forward  what  I  consider 
positive  proofs  that  this  fever  [typhoid]  is  produced  by  emanations 
from  decaying  organic  matter,  and  I  would  therefore  suggest  for  it  the 
appellation  of  pythogenic  fever  —  irvdoyevrjs  and  yewaw." 

Murchison's  views  were  urged  at  great  length  and  with  much  plausi- 
bility in  the  first  edition  of  his  work  (1862)  on  continued  fevers,  in 
which  occur  statements  like  the  following  :  "  Pythogenic  [typhoid] 
fever  is  often  generated  spontaneously  by  faecal  fermentation"  (p.  455). 

The  doctrine  was  vigorously  criticised  and  opposed  by  the  "con- 
tagionists,"  especially  by  Dr.  William  Budd  of  Bristol,  and  in  the 
second  edition  (1873)  of  Murchison's  "Continued  Fevers"  was  con- 
siderably modified  and  restricted,  although  we  find  in  that  the  follow- 
ing definition  of  pythogenic  [typhoid]  fever  :  "An  endemic  disease 
generated  and  propagated  by  certain  forms  of  decomposing  organic 
matter"  (p.  417).  And  again:  "It  may  be  generated  independently 
of  a  previous  case  by  fermentation  of  faecal,  and  perhaps  other,  forms 
of  organic  matter.  It  may  be  communicated  by  the  sick  to  persons  in 
health,  but  even  then  the  poison  is  not,  like  that  of  smallpox,  given  oflf 


Il6     ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

from  the  body  in  a  virulent  form,  but  is  developed  by  the  decomposi- 
tion of  the  excreta  after  their  discharge.  Consequently  an  outbreak 
of  enteric  [typhoid]  fever  implies  poisoning  of  air,  water  or  other 
ingesta  with  decomposing  excrement." 

In  these  statements  it  is  easy  to  see  that  Murchison  was  a  believer  in 
the  spontaneous  generation  of  specific  disease  in  or  through  filth,  an  idea 
unfortunately  still  widely  prevalent,  but  wholly  without  foundation  in 
fact.  In  regard  to  a  closely  related  infectious  disease  typhus  (jail  fever, 
ship  fever,  spotted  fever),  which  has  often  been  attributed  to  filth  as  a 
source,  whereas  filth  is  probably  only  its  efficient  vehicle,  Murchison 
went  even  further,  asserting  its  spontaneous  origin  in  such  conditions  as 
overcrowding  and  bad  ventilation  :  "  Typhus,  the  grand  predisposing 
cause  to  which  is  destitution  ;  while  the  exciting  cause  or  specific 
poison  is  generated  by  overcrowding  of  human  beings  with  deficient 
ventilation"  (Edin.  Med.Journ.,  1858,  p.  322). 

The  modern  theories  of  filth  and  its  dangers  are  very 
different  from  these.  Filth  is  first  and  always  a  conven- 
ient vehicle  of  disease  ;  but  as  a  rule,  in  temperate  climates, 
it  is  probably  nothing  more  than  this  unless  it  be  also  a  de- 
pressing, or  unfavorable,  "  predisposing  "  condition.  The 
earlier  view  which  saw  in  filth  a  necessary  phase  in  the 
life-history  of  certain  infectious  micro-organisms  is  now 
abandoned,  and  it  is  to-day  very  doubtful  whether  the  germs 
of  most  infectious  diseases  ordinarily  find  accumulations  of 
filth  suitable  for  their  multiplication.  There  is  no  question 
that  the  micro-organisms  of  disease  may  under  favorable 
conditions  occur  or  survive  for  a  long  time  in  filth,  and  it 
is  probable  that  under  certain  conditions  of  warmth,  food- 
supply  and  the  absence  of  enemies  they  may  even  multiply ; 
but  it  appears  probable  that  such  conditions  do  not  often 
occur  in  nature,  unless  perhaps  occasionally  in  tropical  coun- 
tries. The  most  natural  and  the  most  favorable  means  for 
the  conveyance  of  disease  germs  appears  to  be  that  which  is 
quickest  and  most  direct,  namely,  contagion,  or  the  transfer 
directly  from  one  individual  to  another  without  the  inter- 
position of  the  earth,  the  atmosphere  or  other  extraneous 
influences.  Contrary  to  Murchison's  view,  the  longer  the 
journey,  and  the  more  the  time  spent  in  making  the  jour- 


FILTH  AND   FILTH   DISEASES  1 17 

ney,  from  patient  to  victim,  the  less  is  the  likelihood  of  the 
successful  transmission  of  the  disease.  The  interposition 
of  filth  or  earth  or  air  or  water  doubtless  tends  in  most 
cases  to  the  diminution  of  danger,  owing  to  the  unfavorable 
conditions  of  one  sort  or  another  encountered  by  the  germs 
en  route. 

Filth  is  looked  upon  by  the  sanitarian  of  to-day,  there- 
fore, as  dangerous  chiefly  because  it  may  contain  the  more 
or  less  attenuated  germs  of  disease,  and  not  so  much  as 
formerly  because  it  may  be  a  "breeding-place"  for  such 
germs.  It  is  a  vehicle  rather  than  a  source ;  and  when  it 
is  pulverized  it  may  cause  an  atmosphere  in  its  vicinity  to 
become  infected ;  or  when  handled  it  may  find  its  way  to 
the  mouth,  or  when  occurring  upon  fruits,  vegetables,  in 
milk,  in  water  or  any  other  substances  likely  to  enter  the 
mouth  without  having  first  been  sterilized,  —  and  in  all 
these  cases  it  is  obviously  dangerous  as  a  vehicle. 

With  these  views  of  filth  and  its  sanitary  significance 
the  older  notions  of  "  filth-diseases "  have  faded  away. 
Those  diseases  to-day  are  simply  ordinary,  zymotic  (infec- 
tious) diseases  in  which  the  vehicle  of  the  causative  germs 
is  filth  of  some  sort. 

§  8.  —  The  PJiilosophy  of  Cleanness 

From  what  has  now  been  said,  it  is  easy  to  perceive  the 
modern  philosophy  of  cleanness.  Dirt  is  dangerous,  not 
because  it  is  "  of  the  earth,  earthy,"  but  because  it  is  too 
often  " drit"  or  excrement;  and  the  love  of  cleanness  or 
the  abhorrence  of  dirt,  which  is  gradually  becoming  estab- 
lished in  all  highly  civilized  peoples,  is  doubtless  a  result- 
ant of  the  dearly  bought  experience  of  the  race,  which  has 
shown  that  dirt  is  dangerous  and  therefore  to  be  dreaded. 
Cleanness,  or  the  absence  of  dirt,  is  not  merely  an  aesthetic 
adornment,  —  though  doubtless  an  acquired  taste ;  it  is 
above  all  a  sanitary  safeguard,  the  importance  of  which 


Il8    ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

has  been  learned  by  hard  experience.  In  other  words,  to 
be  clean  is,  in  a  measure,  to  be  safe  from  infectious  disease ; 
and  cleanness  applies  not  only  to  the  person  but  extends 
also  to  the  personal  environment,  and  especially  to  the 
food  supply,  the  water  supply,  the  milk  supply,  etc. 

Probably,  the  greatest  sanitary  step  ever  taken  by  the 
race  was  the  application  of  high  temperatures  to  the  prepa- 
ration of  food,  i.e.  cookery.  There  is  very  little  doubt 
that  far  more  important  than  any  increase  in  the  digesti- 
bility of  food  effected  by  cookery  is  the  destruction  of 
parasites,  visible  and  invisible,  within  it  thus  brought  about. 
Charles  Lamb  was  probably  right  in  attributing  the  love 
of  cookery  to  the  improvement  in  the  flavors  of  food  which 
it  occasions,  as  is  described  in  his  well-known  version  of  the 
discovery  in  the  case  of  roast  pig ;  and  yet  there  is  every 
reason  to  believe  —  as  has  only  lately  become  recognized  — 
that  the  sanitary  improvement  wrought  by  the  discovery 
of  cookery  was  even  more  important  than  either  the 
gustatory  or  the  nutritive  improvement.  It  is  difficult  to 
see  how  infection  could  have  been  otherwise  than  very 
common  and  very  disastrous  before  the  invention  of  cook- 
ery, for  even  to  this  day  uncooked  food  forms  one  of  the 
principal  vehicles  for  the  conveyance  of  parasites  and 
disease  germs. 

§  9. — Personal  versus  Public  Cleanness 

It  follows  as  a  matter  of  course  that  personal  cleanness 
is  more  important  than  public  cleanness.  In  other  words, 
that  the  avoidance  of  personal  filth  is  far  more  necessary 
than,  for  example,  is  cleanness  of  streets,  dooryards,  alleys 
and  the  like.  And  yet,  as  is  pointed  out  and  emphasized 
beyond  (p.  221),  public  supplies  are  public  dangers.  If 
the  public  water  supply,  for  example,  be  infected,  no 
matter  how  scrupulously  clean  the  residents  of  a  city  may 
be  in  respect  to  their  persons,  they  will  run  very  serious 


THE   SANITARY   SIGNIFICANCE   OF  COOKERY     119 

risks  of  disease  if  they  drink  from  it.  The  same  thing 
may  be  said  of  the  public  milk  supply;  and  nothing  is 
more  impressive  to  the  practical  sanitarian  than  to  witness 
an  epidemic  of  typhoid  fever  in  a  wealthy  and  well-cared- 
for  quarter  of  a  city,  where  the  inhabitants  are  personally 
clean,  the  houses  are  unexceptionable,  the  plumbing  per- 
fect, the  drains  in  good  condition,  the  tableware  and  linen 
spotless,  and  yet  typhoid  fever  is  present  perhaps  in 
nearly  every  family,  because  of  a  polluted  and  infected 
milk  supply  or  water  supply.  It  must  never  be  forgotten 
that  the  sanitary  chain  is  no  stronger  than  its  weakest  part, 
and  that,  no  matter  how  clean  and  wholesome  all  other 
conditions  may  be,  if  there  is  one  point  from  which  the 
germs  of  infectious  disease  may  find  admission  into  the 
body,  danger  may  be  imminent.  Nothing  is  more  instruc- 
tive than  to  discover  cities  or  towns  in  which  great  com- 
plaint is  made  of  filth  in  the  streets,  —  from  which,  after 
all,  comparatively  little  danger  is  likely  to  come, — while 
an  impure  water  supply  or  milk  supply  is  being  used  with 
absolute  confidence,  or  blindness,  or  ignorance. 

§  10. — Public  Drinking-cups  and  their  Dangers 

It  not  infrequently  happens  that  the  same  persons  who 
complain  loudly  and  rightly  enough,  perhaps,  of  dirty  streets, 
and  are  quick  to  blame  public  officials  for  their  laxity 
in  this  respect  will,  nevertheless,  at  fountains,  in  railway 
trains  or  in  theatres,  apply  their  own  lips  to  public  drink- 
ing-cups  which  a  few  minutes  before  have  been  touched 
by  the  lips  of  strangers,  possibly  suffering  from  infectious 
diseases,  such  as  tuberculosis  or  diphtheria.  It  should 
require  only  a  moment's  consideration  to  show  how  great 
is  the  risk  run  under  these  circumstances,  and  how 
inconsistent  is  the  criticism  bestowed  by  one  who  thought- 
lessly takes  these  grave  risks  when  he  cries  out  at  the 
relatively  remote  dangers  of  dirty  streets.  What  has  been 


120    ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

said  about  drinking-cups  applies  obviously  to  communion- 
cups,  "roller"  towels,  razors  in  barber  shops,  unclean 
dishes,  spoons,  etc.,  and  requires  no  further  comment. 
The  dangers  of  these  things  are  too  obvious  to  need 
emphasis.  A  sanitary  fountain  has  been  devised,  and  is 
in  use  in  many  places,  to  do  away  with  the  public  drink- 
ing-cup,  and  in  so  far  as  it  is  successful  in  doing  this, 
it  deserves  the  warm  commendation  of  sanitarians.  The 
arrangement  by  which  this  is  accomplished  is  very  simple ; 
and  for  use  in  public  places,  schools,  institutions  and  the 
like,  it  promises  to  be  of  great  assistance.  No  cup  what- 
ever is  required,  but  any  one  who  wishes  simply  leans  over 
and  drinks  from  a  little  fountain  provided  for  the  purpose. 
Every  instant,  of  course,  the  water  supply  is  changing,  and 
if  infectious  micro-organisms  should  be  for  an  instant 
deposited  by  A,  they  are  necessarily  the  next  instant 
washed  away  before  B  can  come  in  contact  with  them. 
It  has  long  been  the  custom  in  certain  factories  abun- 
dantly supplied  with  water,  to  keep  rising,  in  the  middle 
of  a  basin  of  convenient  height,  a  small  jet  of  water,  from 
which  the  thirsty  might  drink.  Small  fountains  of  this 
kind  can  easily  be  arranged  in  many  public  places,  doing 
away  altogether  with  the  common  drinking-cup,  which, 
wherever  found,  is  a  sanitary  abomination. 

§  ii. —  The  Disposal  of  Dirt,  Dust,  Garbage  and  Refuse 

From  the  point  of  view  of  the  sanitarian  the  disposal  of 
garbage  and  refuse  is  largely  a  question  of  engineering. 
By  "garbage"  is  usually  meant  the  more  solid  organic 
wastes  of  the  kitchen,  the  more  liquid  wastes  being  dis- 
charged through  the  sink-pipe  into  the  sewer.  By  "  refuse  " 
is  meant  household  wastes  such  as  dirt,  ashes,  papers, 
boxes,  dust,  bottles  and  the  like,  which  are  only  in  part 
combustible.  It  is  from  the  sanitary  point  of  view  de- 
sirable to  get  rid  promptly  and  effectually  of  both  garbage 


MUNICIPAL   SANITATION  121 

and  refuse,  for  these  may  contain  the  germs  of  infectious 
disease,  and  their  destruction  or  disinfection  by  fire  —  the 
quickest  and  most  certain  of  all  disinfectants  —  is  highly 
desirable.  What  is  not  desirable  is  that  garbage  should 
be  fed  to  cows  used  as  sources  of  milk  supply,  not  because 
of  the  dangers  of  infection,  but  because  of  the  poor  quality 
of  milk  likely  to  result.  There  is  less  objection,  if  any,  to 
the  disposal  of  garbage  by  feeding  it  to  swine,  or  by  carry- 
ing it  to  sea  or  by  ploughing  it  into  the  living  earth,  which 
latter  readily  disposes  of  it  as  of  stable  manure.  Various 
methods  for  the  disposal  of  garbage  and  refuse  are  in  use ; 
but  while  cremation,  for  the  reasons  given,  is  undoubtedly 
the  most  desirable,  the  sanitary  aspects  of  the  matter  do 
not  appear  to  be  especially  important  so  long  as  garbage 
and  refuse  are  removed  from  dwellings  or  groups  of  dwell- 
ings, such  as  cities,  and  somehow  effectively  disposed  of. 
Those  who  desire  to  enter  further  into  this  subject  may  be 
referred  to  Chapin's  "  Municipal  Sanitation  in  the  United 
States,"  Providence,  R.  I.,  1901 ;  to  Goodrich's  "  Disposal 
of  Town's  Refuse,"  N.  Y.  (Wiley) ;  London  (P.  S.  King), 
1901 ;  and  to  Baker's  "  Municipal  Engineering  and  Sani- 
tation," N.  Y.  (Macmillan),  1902. 

§  12.  —  Cleanness,  Asepsis  and  Antisepsis 

Inasmuch  as  dirt  is  richly  laden  with  micro-organisms, 
the  agents  of  fermentation,  putrefaction  and  decay,  it  is 
plain  that  the  absence  of  dirt,  or  cleanness,  must  go  far  to 
prevent  these  processes.  It  is  clear,  for  example,  that 
punctures  of  the  skin  made  by  instruments  absolutely  free 
from  organisms  cannot  convey  infection ;  that  the  knife  of 
the  surgeon  if  absolutely  clean  cannot  cause  "dissecting 
wounds  " ;  that  cookery  of  foods  must  tend  to  defer  their 
decay:  in  short,  that  absolute  cleanness  is  equivalent  to 
asepsis,  and  partial  cleanness  is  an  antiseptic  correspond- 
ing in  efficiency  to  its  extent.  This  is  now  so  fully  recog- 
nized that  dirt  is  to-day  regarded  as  the  principal  foe  of 


122    ON  FILTH  AND  THE  PHILOSOPHY  OF  CLEANNESS 

the  surgeon;  and  probably  the  cleanest  rooms  that  have 
ever  been  known  either  in  modern  times  or  in  the  past,  are 
the  operating  rooms  of  the  hospitals  of  to-day. 

In  certain  industrial  pursuits  experience  is  teaching  a 
similar  lesson.  By  drawing  milk  from  healthy  cows  with 
extreme  precautions  as  to  cleanness,  it  is  possible  to  have  it 
keep  sweet  (if  refrigerated)  during  the  whole  period  of  a 
trans-Atlantic  voyage.  Various  other  dairying  processes 
are  also  favored,  if  not  conditioned,  by  cleanness;  can- 
ning and  preserving  are  far  more  successfully  carried 
out  if  done  with  scrupulous  regard  for  cleanness ;  and  it 
is  no  exaggeration  to  say  that  in  all  human  affairs  clean- 
ness —  which  means  the  exclusion  or  destruction  of  germ 
life  —  is  the  keynote  of  successful  sanitation. 


CHAPTER  VII 

ON  SEWAGE  AS  A  VEHICLE  OF  DISEASE.  ITS  PROPER  DIS- 
POSAL AND  PURIFICATION.  THE  NATURAL  PURIFICATION 
OF  SEWAGE  BY  FERMENTATION  AND  THE  LIVING  EARTH 

"  If  we  neglect  this  subject,  we  cannot  expect  to  do  so  with  impu- 
nity." —  MICHAEL  FARADAY,  on  "  The  Filth  of  the  Thames."  London, 
1854. 

"  The  sewer  ...  is,  so  to  speak,  the  direct  continuation  of  the  .  .  . 
intestine.1'  —  WILLIAM  BUDD,  on  "Typhoid  Fever."  London,  1873. 

"  The  bills  of  mortality  are  more  obviously  affected  by  drainage 
than  by  this  or  that  method  of  practice."  —  OLIVER  WENDELL 
HOLMES,  on  "Border  Lines  of  Knowledge,"  etc.  Boston,  1862. 

§  I.  —  The  Disposal  and  Disinfection  of  Excreta 

SINCE  there  is  reason  to  believe,  as  has  been  shown  in 
Chapter  V,  that  the  excreta  of  man  and  other  animals  are 
the  principal  original  vehicles  of  infection  and  contagion, 
one  of  the  first  problems  of  sanitation  is  the  safe  disposal 
and  disinfection  of  excreta.  Various  devices  for  the  dis- 
posal of  the  wastes  of  animal  life  have  had  their  day,  but 
only  two  need  now  be  mentioned,  viz.,  the  "  dry-earth  " 
system  and  the  "water-carriage,"  or  "sewerage,"  system. 
The  former  was  at  one  time  in  high  repute,  and  in  some 
cases,  as  in  farm-houses,  country-houses,  and  villages,  is 
still  useful,  especially  if  water  is  scarce  or  difficult  to  get. 
It  is  open,  however,  to  the  grave  sanitary  objection  that 
although  dry  earth  deodorizes  well,  it  does  not  necessarily 
disinfect ;  while  on  the  practical  side  the  system  is  much 
less  convenient  than  disposal  by  water-carriage.  The  in- 
troduction of  running  water  for  other  purposes,  even  into 
farm-houses  and  villages,  has  also  greatly  favored  disposal 

123 


124  ON   SEWAGE   AND   ITS   PURIFICATION 

by  sewerage ;  so  that  the  windmill  and  the  cesspool  have 
made  unnecessary  almost  anywhere  either  the  earth-closet 
or  the  privy.1  In  view  of  the  now  limited  use  of  the  dry- 
earth  system  we  need  not  dwell  upon  it  further. 

In  the  water-carriage  (or  sewerage)  system,  which  is 
now  so  generally  adopted  and  so  familiar  as  to  require  no 
description  the  vehicle  of  infection  is  sewage.  This  sub- 
stance is  of  special  and  fundamental  importance  in  sani- 
tary science,  first,  because  of  its  character  as  a  common 
carrier  of  excreta  and  a  vehicle  of  infection;  second, 
because  of  its  ubiquity  and  abundance  in  modern  life ; 
and  third,  because  it  may  contain  not  only  the  bowel 
discharges  and  urine  of  the  diseased,  but  also  the  excreta 
from  the  mouth  and  the  skin.  In  brief,  sewage  may  be 
made  up  of  all  the  original  vehicles  of  disease, — the 
excreta  from  the  skin;  from  the  alimentary  and  pul- 
monary, and  from  the  genito-urinary  tracts ;  and  it  is  also 
subject  to  indirect  infection  from  infected  earth,  air  and 
water  serving  as  secondary  vehicles. 

\  The  cleansing  and  disinfection  of  sewage  is  commonly 
described  as  its  "  purification,"  but  before  proceeding  to 
consider  this  problem,  one  of  the  most  pressing  and  one 
of  the  most  difficult  of  the  sanitary  arts,  we  must  inquire 
somewhat  more  closely  concerning  the  nature  of  sewage, 
its  origin  and  its  fate. 

§  2.  —  Sewage :  its  Genesis  and  Composition 

The  word  "sewage"2  signifies  "drainage"  and  may  be 
defined  as  the  contents  of  drains ;  but  it  must  be  distinctly 

1  For  an  elaborate  defence  of  the  sanitary  efficiency  of  the  Dry-earth  Sys- 
tem, see  Buchanan,  Twelfth  Ann.  Rep.  Med.  Off.  Privy  Council,  1869.    Per 
contra,  see  Sinnhuber,  Inaug.  Diss.  Konigsberg,  under  Esmarch.    Baumgarten's 
fahresbericht,  XII  (1896),  844. 

2  In  common  parlance  the  terms  "  sewage  "  and  "  sewerage  "  are  often 
confounded.      It   is  usual,  however,  as  it  is  certainly  preferable,  to  reserve 
the  latter  for  the  system  of  sewers,  and  to  use  always  the  word  "  sewage  "  for 
the  liquid  contents  of  sewers. 


SEWAGE    VS.   SEWERAGE 


125 


understood  that  the  drains  in  this  case  shall  be  house  drains 
and  shall  contain  domestic  drainage.  £_  The  under-drains  of 
a  wet  piece  of  uninhabited  land,  for  example,  contain 
drainage  but  no  sewage,  the  idea  of  sewage  being  con- 
nected exclusively  with  the  drainage  of  houses  and  human 
beings,  or  at  least  with  the  wastes  of  animal  life.})  Sewage 
is  composed  ordinarily  of  the  washings  of  sinksTthe  empty- 
ings of  water-closets,  the  discharges  from  laundries,  bake- 
shops,  stables  and  similar  places,  together  with  the 
rain  water  from  roofs  and  the  washings  of  streets.  It 
may  also  contain  the  refuse  from  slaughter-houses,  pus 
and  other  substances  from  hospitals,  the  washings  of 
markets  —  in  fact,  almost  anything  capable  of  carriage  by 
water,  and  small  enough  to  find  entrance  into  sewers. 
The  excreta  of  human  beings,  washings  from  the  skin, 
sputum,  bowel  discharges,  urine,  —  in  short,  all  excreta 
excepting  the  breath,  —  may  be  present  in  sewage. 

Nevertheless,  ordinary  American  sewage,  on  account 
of  its  vast  dilution,  is  much  less  objectionable  to  look 
at  than  is  commonly  supposed  and  it  often  merely  sug- 
gests in  appearance  dish-water  or  dilute  milky  liquids 
with  some  dirt  in  suspension.  The  average  composition 
of  the  fresh  domestic  sewage  of  an  American  city  (Law- 
rence, Mass.)  for  1897  was,  during  the  morning,  when 
the  sewage  was  relatively  strong,  as  follows  (parts  per 
100,000):  — 


s  ^ 

ALBUMINOID  AMMONIA 

H 

NITROGEN  AS  — 

*g 

y 

<  3 

1 

O  § 

wo  P  8 

W  0 

w  5 
K  * 
fe 

Total 

Soluble 

Insoluble 

3 

u 

Nitrates 

Nitrites 

5  | 

y  M  w  w 
<  So  s 

3-19 

1.26 

.78 

.48 

13.36 

.18 

.0182 

7-59 

4,726,000 

The  sewage  of  European  towns  is  usually  much  more 
concentrated  than  that  of  American  cities,  and  is  there- 


126  ON   SEWAGE  AND   ITS   PURIFICATION 

fore    darker    in   color,   less  watery  or   milky   and   more 
objectionable  in  appearance. 

§  3.  —  The  Dangerous  Elements  and  Properties  of  Sewage 

These  consist  chiefly  in  the  disease-producing  organisms 
which  may  be  present.  There  is  every  reason  to  suppose 
that  sewage  free  from  such  organisms  might  be  swallowed 
without  serious  harm,  and  would  be  rather  in  the  nature 
of  a  poor  than  a  dangerous  material.  Inasmuch,  however, 
as  sewage  contains  or  may  contain  the  excreta  of  human 
beings  or  other  animals,  and  inasmuch,  further,  as  has  been 
shown  above,  as  it  is  by  way  of  these  excreta  that  infec- 
tion travels,  sewage  must  always  be  regarded  as  dangerous, 
either  to  come  into  contact  with,  or  to  admit  into  the  body 
through  wounds,  or  in  or  upon  food  materials.  There  is 
reason  to  believe  that  the  only  really  dangerous  properties 
of  sewage  reside  in  the  infectious  elements  referred  to. 
The  ordinary  decomposition  of  sewage  may  indeed  lead  to 
the  generation  of  objectionable  gases,  which  shall  tempo- 
rarily prejudice  or  damage  the  organism.  But  there  is 
every  reason  to  believe  that  the  dangers  of  sewer  gas  have 
been  much  exaggerated,  and  that  many  cases  of  disease 
have  been  charged  to  sewer  gas  which  were  really  due 
to  the  invasion  of  micro-organisms  from  other  and  very 
different  sources.  To  the  consideration  of  this  question 
however,  we  shall  return  hereafter  (Appendix,  p.  347). 

§  4.  —  Importance  of  the  Sanitary  Disposal  of  Sewage 

Inasmuch  as  sewage  may  at  any  time  contain  any  or  all 
of  the  excretions  of  the  animal  body,  and  inasmuch  further 
as  these  may  contain  actively  infectious  materials,  the  safe 
and  proper  disposal  of  sewage  is  one  of  the  first  necessi- 
ties of  sanitary  science  and  the  public  health.  Among 
primitive  and  uncivilized  peoples  no  special  pains  are  taken 
for  the  disposal  of  sewage  or  the  excreta  of  animals,  but 


PRIMITIVE  METHODS   OF   SEWAGE  DISPOSAL      I2/ 

in  civilized  societies  various  and  costly  devices  are  em- 
ployed to  this  end.  The  most  primitive  method  is  that  in 
which  the  wastes  of  life  are  simply  deposited  or  thrown 
out  upon  the  surface  of  the  earth  in  the  neighborhood  of 
human  habitations,  and  when  the  latter  are  widely  separated 
little  or  no  harm  may  result  from  this  practice.  When, 
for  example,  in  country  districts  or  elsewhere,  the  untidy 
housewife  disposes  of  dish-water  by  simply  throwing  it 
from  a  window,  no  particular  harm  may  result  if  the  quan- 
tity thus  disposed  of  is  not  too  great,  and  the  dousing  of 
the  soil  below  is  not  too  frequent,  especially  if  the  soil 
be  open,  porous  or  sandy.  We  shall  shortly  see  that 
in  this  case,  and  in  the  similar  cases  in  which  manure  is 
applied  to  land  in  large  quantities  and  in  successive  years, 
the  organic  wastes  present  are  speedily  mineralized  or 
converted  into  inorganic  matters,  by  the  agency  of  bacteria 
residing  in  the  soil  in  such  overwhelming  numbers  as  to 
form  a  density  of  population  almost  inconceivable,  and 
entitling  us  to  describe  the  surface  layers  of  the  earth  as 
"  the  living  earth." 

§  5. — Disposal  of  Sewage  in  Rivers 

Whenever  a  city  or  town  introduces  a  system  of  sewers, 
it  is  easy  and  natural  in  many  cases  to  dispose  of  the  sew- 
age by  simply  letting  it  run  from  the  principal  sewer  or 
sewers  into  a  neighboring  brook  or  river  or  other  stream. 
It  is  easy,  because  the  natural  drainage  is  in  the  direction 
of  the  river,  which  is  often  little  more  than  the  principal 
natural  drain  of  the  neighborhood.  It  is  natural,  because 
the  river  being,  as  stated,  the  ordinary  drain  of  the  neigh- 
borhood, carries  off  not  only  the  water  which  falls  upon 
its  watershed  but  also  anything  that  will  float  upon  or 
mingle  with  the  water ;  and  in  most  cases  even  before  it  is 
proposed  to  introduce  sewers,  the  stream  has  long  been 
used  as  an  easy  means  of  ridding  the  neighborhood  of 


128  ON   SEWAGE   AND   ITS   PURIFICATION 

rubbish  or  wastes  of  various  descriptions.  It  cannot  be 
denied  that,  in  case  the  amount  of  sewage  to  be  got  rid 
of  is  relatively  small,  and  provided  the  stream  is  nowhere 
below  used  as  a  source  of  water  supply,  this  practice  may 
not  necessarily  be  objectionable;  but  even  in  such  cases  it 
is  generally  unwise,  because  under  slightly  different  condi- 
tions, such  as  growth  of  the  population  upon  the  water- 
shed, or  unexpected  drought,  the  presence  of  a  relatively 
large  amount  of  sewage  may  produce  a  nuisance,  and 
prejudice  the  public  health,  finally  transforming  the  stream 
from  something  capable  of  giving  pleasure,  into  an  open 
sewer  shunned  by  all  mankind. 

How,  then,  it  will  naturally  be  asked,  has  it  happened 
that  so  many  important  cities  and  towns  all  over  the  world 
freely  dispose  of  their  sewage  by  simply  turning  it  into  the 
nearest  watercourse  ?  The  answer  is  easy.  It  is  simply 
because  until  very  lately  engineers,  chemists  and  sanitary 
experts,  alike  held  as  true  a  theory  of  the  purification  of 
watercourses  which  is  now  known  to  be  false,  or,  at  best, 
only  a  half  truth.  This  was  the  famous  theory  of  the  "  self- 
purification  of  streams,"  to  a  brief  consideration  of  which 
we  may  now  turn. 

§  6.  —  Theory  of  the  Self-purification  of  Streams 

This  theory  was  based  upon  the  obvious  fact  that  al- 
though a  very  large  amount  of  sewage  might  be  suddenly 
poured  into  a  stream  at  a  given  point,  so  that  at  that  point 
the  pollution  was  conspicuous  and  self-evident,  it  was  only 
necessary  to  follow  the  stream  for  a  short  distance  to  per- 
ceive that  the  water  had  distinctly  improved  in  appearance. 
This  result  of  mere  inspection  was  strongly  confirmed  by 
the  chemistry  of  the  time,  which  proved  by  actual  analysis 
that  the  organic  matter  in  the  water,  and  the  results  of 
decomposition,  were  decidedly  less  at  the  lower  than  the 
upper  point.  Naturally,  only  one  conclusion  could  be 


THE   "SELF-PURIFICATION"  OF   STREAMS        129 

drawn  from  the  premises.  The  stream  had  somehow  puri- 
fied itself  while  flowing,  and  the  corollary  was  deduced 
that  "running  water  purifies  itself."  (Cf.  p.  231.) 

The  importance  and  far-reaching  effects  of  this  con- 
clusion can  hardly  be  overestimated.  Relying  upon  it, 
numerous  cities  and  towns  all  over  the  world  introduced 
water  supplies  derived  from  sewage-polluted  streams,  and 
infinite  damage  was  done  to  the  public  health.  The  theory 
is  now  abandoned,  or  rather  accepted  only  after  so  much 
modification  that  it  is  virtually  new.  There  is,  indeed,  a 
considerable  purification  effected  by  streams,  but  it  js 
mostly  purification  by  dilution ;  and,  as  we  shall  see  in  a 
later  paragraph,  distrust  of  this  theory  has  produced  pro- 
found changes  in  our  points  of  view.  The  disposal  of 
sewage  in  rivers  is  always  to  be  deprecated  unless  the 
volume  of  sewage  discharged  is  very  small  in  proportion 
to  the  dry  weather  flowage  of  the  stream  in  question.  It 
is  not  to  be  tolerated  if  the  river  below  is,  at  any  point, 
however  remote,  used  without  purification  as  a  source  of 
water  supply ;  and  it  is  often  not  desirable  even  with  such 
purification. 

§  7.  —  Sewage  Disposal  in  Lakes 

Some  cities  are  so  situated  that  it  is  convenient  and 
natural  for  them  to  drain  into  bodies  of  fresh  water,  either 
lakes  or  ponds,  in  which  there  is  little  or  no  current 
such  as  always  exists  in  a  river.  In  these  cases,  the  suc- 
cess of  the  practice,  so  far  as  the  mere  disposal  of  sewage 
goes,  depends  chiefly  upon  the  proportion  maintained  be- 
tween the  volume  of  sewage  and  the  volume  of  the  water 
into  which  it  is  discharged.  This  will  be  seen  most  clearly 
by  simply  considering  the  extremes,  in  which  cases,  for 
example,  a  large  city  empties  its  sewage  into  a  small  pond  ; 
or,  on  the  other  hand,  a  small  town  pours  its  sewage  into 
a  large  lake.  In  the  former  case,  the  results  would  be 
disastrous,  the  pond  being  very  soon  converted  into  a  sew- 


130  ON   SEWAGE   AND   ITS  PURIFICATION 

age  pool.  In  the  latter,  no  perceptible  effect  would  be 
produced.  Obviously,  there  must  be  a  large  class  of  cases, 
comprising  cities  and  towns  of  moderate  size  located  upon 
relatively  large  bodies  of  quiet  water,  which  may  drain  with 
safety  into  lakes  or  ponds ;  but  it  is  equally  clear  that  there 
is  also  another  class  of  cases,  comprising  for  the  most  part 
large  cities,  situated  upon  relatively  small  bodies  of  quiet 
water,  which  cannot  drain  into  these  without  seriously 
prejudicing  their  purity  and  possibly  producing  a  nuisance. 
Furthermore,  the  case  is  complicated  seriously  if  either 
a  city  or  a  town  draining  into  a  lake  or  pond  undertakes  to 
derive  its  water  supply  from  the  same  lake,  or  if  any  other 
city  or  town,  no  matter  how  remote,  makes  such  use  of 
the  water.  This  aspect  of  the  problem,  however,  need  not 
detain  us  at  this  point  but  may  be  reserved  for  the  con- 
sideration which  it  requires  until  a  later  chapter.  It  is 
enough  in  this  connection  to  note  that  very  many  of  the 
cities  and  towns  of  the  United  States  do  as  a  matter  of 
fact  dispose  of  their  sewage  by  emptying  it  into  lakes  or 
ponds,  and  that,  too,  with  entire  success  so  far  as  the  mere 
disposal  of  the  sewage  alone  is  concerned.  Examples  are 
the  cities  and  towns  bordering  the  Great  Lakes,  and  in  the 
list  are  some  cities  of  large  size  such  as  Chicago,  Mil- 
waukee, Duluth,  Cleveland  and  Toronto. 

§  8. — Disposal  in  Harbors,  Estuaries  and  the  Sea 

Another  class  of  cities  and  towns,  and  this  includes  some 
of  the  largest  in  the  world,  are  so  situated  that  their  natural 
drainage  is  either  directly  into  the  sea,  or  into  some  tidal 
harbor  or  estuary.  In  these  cases  it  is  easy  and  natural  to 
dispose  of  sewage  by  simply  pouring  it  into  the  sea,  harbor, 
or  estuary  at  some  convenient  point  or  points ;  and  here, 
also,  as  in  the  preceding  case,  if  the  city  or  town  is  not  too 
large  in  proportion  to  the  volume  of  water  at  its  doors,  no 
harm  comes  from  such  disposal.  There  is,  in  this  case, 


SEWAGE   DISPOSAL  IN   LAKES  AND   THE   SEA     131 

the  obvious  advantage  that  such  bodies  of  water  are  never 
used  as  sources  of  water  supply,  so  that  one  serious  ele- 
ment of  difficulty  which  exists  in  the  case  of  lakes  and 
other  bodies  of  fresh  water  may  here  be  neglected.  As 
a  matter  of  fact,  numerous  cities  and  towns  on  our  own 
coasts  pour  their  sewage  into  salt  or  brackish  waters,  often 
with  entire  success  and  with  the  absence  of  all  complaint. 
It  is  only,  indeed,  in  very  rare  cases,  that  this  system  of 
disposal  causes  trouble,  and  in  these  instances  the  cities 
are  usually  situated  not  directly  on  the  sea  itself,  but  upon 
some  narrow  arm  of  the  sea  or  some  tidal  river  which 
virtually  limits  the  size  of  the  body  of  water  into  which 
the  sewage  is  poured.  Such  a  case  is  that  of  London, 
which  is  situated  not  upon  the  sea,  but  upon  a  tidal  river, 
and  even  in  the  case  of  London  the  sources  of  complaint 
have  been  based  more  upon  the  alleged  obstruction  to 
navigation  caused  by  deposits  in  the  shallow  river  than 
upon  sanitary  grounds.  No  such  complaints,  at  least  of 
a  serious  character,  have  as  yet  arisen  in  the  case  of  cities 
like  New  York,  Philadelphia  or  Boston,  or  indeed,  so  far 
as  the  writer  is  aware,  in  any  instance  excepting  that  of 
London  ;  so  that  we  may  probably  conclude  that  disposal  in 
the  sea  or  in  its  harbors  or  estuaries  may  safely  be  regarded 
as  one  of  the  most  satisfactory  methods  of  sewage  disposal 
hitherto  discovered  or  employed. 

§  9.  —  Principles  involved  in  the  Disposal  of  Sewage  in 
Rivers,  Lakes,  Estuaries  and  the  Sea 

In  all  these  cases  the  fundamental  principle  of  purifica- 
tion, and  the  basis  of  successful  disposal,  is  simple  dilution, 
by  a  relatively  large  volume  of  purer  water.  Other  factors 
may  or  may  not  cooperate  as,  for  example,  in  the  case  of 
a  swiftly  flowing  river.  The  mere  fact  of  removal  some- 
times constitutes  an  important  contribution  to  successful 
sewage  disposal,  the  sewage  being  speedily  carried  away 


132  ON   SEWAGE   AND   ITS   PURIFICATION 

to  a  point  where  its  existence  is  of  little  consequence,  as 
for  example,  may  happen  in  an  estuary  or  tidal  river,  the 
mere  movement  of  the  water  constituting  an  efficient 
method  of  transportation  of  the  sewage  from  a  point 
where  it  would  be  objectionable  to  a  point  where  its  pres- 
ence is  unobjectionable.  But  this  is  not  all.  Dilution  is 
the  fundamental  phenomenon,  and  lies  at  the  bottom  of 
much  of  the  purification  which,  undoubtedly,  takes  place  in 
all  these  cases.  Mere  removal  does  not,  in  itself,  contrib- 
ute to  purification,  while  dilution  certainly  does  do  so. 
There  are,  however,  other  forces  at  work  which  contribute 
materially  to  purification  by  dilution,  and  these  are  best 
seen  and  studied  in  the  case  of  the  discharge  of  sewage 
into  the  relatively  quiet  waters  of  a  lake,  where  they  are 
not  complicated  or  masked  by  currents,  or  by  the  flowing 
of  a  stream.  Such  instances  are  common  and  easily 
studied,  and,  as  an  example,  we  may  take  the  case  pre- 
sented by  the  sewage  disposal  of  Burlington,  Vt.  (Cf. 

P-  234-) 

Burlington  is  a  city  of  fifteen  thousand  inhabitants,  situ- 
ated on  Burlington  Bay,  a  broad  easterly  expansion  of 
Lake  Champlain.  The  sewage  of  the  city  is  collected  into 
one  large  outfall  sewer  which  empties  near  the  southern 
extremity  of  the  city  directly  upon  the  lake  front  into  the 
waters  of  the  lake.  At  this  point  Lake  Champlain  is  so 
broad  that  the  only  currents  perceptible  are  those  produced 
by  winds,  and,  accordingly,  these  move  sometimes  in  one 
direction,  sometimes  in  another,  but  as  a  rule  are  confined 
to  the  surface,  so  that,  on  the  whole,  there  is  very  little 
motion  of  the  lake  water  in  any  particular  direction.  The 
author  has  made  repeated  examinations  of  the  sewage  in 
the  outfall  sewer  and  of  the  mixed  water  and  sewage  at 
various  points  within  one  mile  of  the  sewer  outlet,  and  the 
results  show  that  while  the  crude  sewage  is  not  materially 
different  from  that  observed  in  most  American  cities,  and 
contains  in  round  numbers  about  one  million  of  bacteria 


SEWAGE  PURIFICATION  BY  DILUTION,  ETC.      133 

per  cubic  centimetre,  the  lake  water  even  one  hundred  feet 
away  shows  already  only  perhaps  a  thousand,  which  num- 
ber rapidly  declines  as  we  recede  from  the  sewer,  until  at 
a  distance  of  a  half  mile  and  more  it  begins  to  be  difficult 
to  find  any  evidence  of  the  presence  of  sewage,  either 
by  chemical  or  by  bacteriological  analyses. 

A  little  reflection  will  show  that  the  mere  dilution  of 
the  relatively  small  amount  of  sewage  by  the  relatively 
enormous  volume  of  the  lake  would  alone  account  for  most, 
if  not  all,  of  the  facts  in  the  case.  But  there  is  good 
reason  to  believe  that  other  factors  of  purification  exist  and 
have  their  influence.  In  the  first  place,  many  of  the  sewage 
bacteria,  and  probably  all  of  the  most  dangerous,  are  by 
preference  thermophilous,  or,  so  to  speak,  warm-blooded, 
having  recently  come  from  the  bodies  of  warm-blooded 
animals  in  which  they  have  existed  and  perhaps  thriven. 
These,  therefore,  find  the  temperature  of  sewage  hardly 
favorable  to  their  continued  existence  or  development,  and 
when  plunged  into  the  still  colder  waters  of  the  lake  are 
subjected  to  conditions  far  less  favorable.  In  the  next 
place,  in  the  bodies  of  their  hosts  these  bacteria  have  found 
not  only  a  favorable  temperature,  but  also  rich  supplies 
of  food.  Once  they  begin  to  travel  through  soil  pipes  and 
sewers,  their  food  becomes  scarcer  and  less  available,  and 
when  finally  they  mingle  with  the  waters  of  the  lake, 
which  are  relatively  pure  and  destitute  of  organic  matters, 
their  pabulum  must  be  distinctly  scanty.  At  the  same 
time,  in  sewage  and  in  the  lake,  they  are  subject  to  the 
influence  of  gravity  which  tends  to  draw  them  down  into 
the  deeper,  quieter  layers  and  finally  into  the  mud  at  the 
bottom,  while  predatory  infusoria  ranging  through  the 
water  may  devour  them  altogether.  Lastly,  if  they  tend  to 
float  or  linger  on  the  surface,  they  may  there  suffer  from 
the  germicidal  action  of  the  rays  of  light  and  perish. 

All  of  these  unfavorable  influences  which  accompany 
the  ordinary  process  of  dilution  in  lakes,  rivers,  estuaries 


134  ON   SEWAGE  AND  ITS  PURIFICATION 

and  the  sea  may  be  either  hindered  or  exaggerated  by 
movement  of  the  water,  such  as  occurs  in  a  flowing  stream, 
or  in  tides  and  other  currents,  and  they,  and  all  other  con- 
ditions tending  to  the  inhibition  of  the  growth,  or  to  the 
destruction  altogether,  of  microbic  life,  may  all  be  summed 
up  in  one  phrase,  namely,  "unfavorable  environment." 
There  is  reason  to  believe  that  the  purification  of  sewage 
by  dilution,  in  respect  at  least  to  its  living,  organic  con- 
tents, is,  as  a  matter  of  fact,  considerable,  though  often 
incomplete,  and  that  the  forces  enumerated  and  which  we 
have  described  collectively  as  "unfavorable  environment" 
play  the  principal  part  in  whatever  purification  actually 
takes  place.  Inasmuch,  however,  as  many  micro-organisms 
are  capable  of  successfully  resisting  for  a  long  time  the 
effects  of  an  unfavorable  environment,  bacteria  being  in 
some  cases  especially  resistant,  it  is  easy  to  understand 
that  the  purification  of  sewage  by  dilution,  even  when 
accompanied  by  the  factors  mentioned,  is  often  incomplete 
and  never  to  be  relied  upon,  except  in  the  presence  of  sat- 
isfactory evidence.  In  the  case  of  sewage  disposal  in  salt 
water  this  is  a  refinement  of  small  consequence,  but  in  the 
case  of  fresh  waters,  such  as  lakes  and  rivers,  which  it  may 
be  desirable  to  use  for  public  water  supplies  at  points 
more  or  less  remote  from  the  place  of  disposal,  the  ques- 
tion assumes  the  highest  possible  importance,  and  to  this 
aspect  of  the  subject  we  shall  return  in  Chapter  IX. 

§  10.  —  Purification  of  Sewage  by  the  Living  Earth 

Reference  has  already  been  made  above,  in  §  4,  in 
some  detail  to  the  primitive  method  of  sewage  disposal 
in  which  the  wastes  of  life  are  got  rid  of  by  simply 
throwing  them  upon  the  earth.  In  this  case,  and  in  the 
similar  case  in  which  manure  is  applied  to  land  in  large 
quantities  and  for  many  successive  years,  the  organic 
wastes  present  are  speedily  mineralized,  or  converted  into 


SEWAGE  AND  THE  LIVING  EARTH  135 

inorganic  matters  by  the  agency  of  micro-organisms  (bac- 
teria) which  reside  in  the  surface  layers  of  the  earth  in 
astonishing  numbers. 

The  commonly  received  idea  of  the  earth,  that  it  is 
typically  inorganic  and  lifeless,  has  been  shown  by  modern 
researches  to  be  singularly  incorrect.  Every  one  is  aware 
that  various  living  things,  such  as  woodchucks,  moles, 
snakes,  and  even  certain  birds,  as  well  as  numerous  insects 
and  innumerable  plants,  spend  a  part  or  the  whole  of  their 
existence  in  the  earth.  And  yet,  when,  in  1881,  Darwin 
drew  general  attention  to  the  enormous  number  of  earth- 
worms living  in  the  upper  layers  of  the  earth,  his  treatise 
occasioned  widespread  surprise.  All  these  forms  of  life, 
however,  are  as  nothing  in  comparison  with  the  myriads 
of  bacteria  which  have  their  home  in  the  earth.  A  single 
grain  of  garden  soil,  for  example,  may  contain  as  many  as 
a  hundred  thousand  of  these  microscopic  organisms,  and 
there  is  reason  to  believe  that  the  soft,  clammy  feel  of 
moist  loam  is  in  no  small  measure  due  to  the  presence  of 
bacterial  bodies.  In  many  cases  the  inorganic  grains 
which  loam  contains  are  mantled,  as  it  were,  by  a  jelly- 
like  substance,  probably  produced  by  these  organisms,  and 
in  which  their  bodies  are  embedded.  It  is  no  exaggera- 
tion, therefore,  at  present,  to  speak  of  the  surface  layers 
of  the  earth,  especially  in  fertile  regions,  as  if  they  were 
alive,  or  of  the  upper  layers  of  the  earth  itself  as  con- 
stituting a  "  living  "  rather  than  a  lifeless  earth. 

If  now  we  consider  what  may  take  place  when  the 
organic  wastes  of  life  are  thrown  upon  this  porous,  living 
earth,  we  may  perhaps  understand  the  remarkable  process 
of  purification  which  takes  place.  When,  for  example,  the 
farmer  periodically  dresses  his  fields  with  manure  consist- 
ing largely  of  the  wastes  of  animal  life,  we  need  not  be 
surprised  if,  after  a  time,  these  wastes  seem  to  have  dis- 
appeared, while  the  soil  upon  which  they  were  placed  has 
grown  correspondingly  soft  and  rich.  Precisely  as,  under 


136  ON   SEWAGE  AND   ITS   PURIFICATION 

similar  circumstances,  the  earthworms  which  are  present 
appear  to  flourish  and  multiply  under  the  favorable  condi- 
tions provided  for  them  by  the  farmer,  so,  we  have  reason 
to  believe,  the  infinitely  smaller  micro-organisms  —  which, 
like  the  earthworms,  reside  in  the  upper  layers  of  the 
earth,  —  feed,  flourish  and  multiply  upon  the  food  thus 
provided  for  them ;  and  exactly  as  the  earthworms  work 
over  the  materials  upon  which  they  feed,  reducing  them 
in  chemical  complexity,  and  turning  organic  into  inorganic 
matters,  so  the  myriads  of  micro-organisms  which  surround 
them  on  every  hand  do  their  appointed  work,  and  min- 
eralize the  organic  wastes  upon  which  they  too  feed  and 
fatten. 

If  what  has  just  been  said  is  true,  it  is  easy  to  under- 
stand how  it  is  that  even  repeated  applications  of  large 
amounts  of  organic  matters,  such  as  stable  manure,  may  be 
successfully  made  to  a  given  area  of  land ;  or  how  it  hap- 
pens that  the  untidy  housewife  may,  with  comparative  im- 
punity and  for  a  long  period,  habitually  throw  from  the 
window  upon  a  limited  piece  of  earth  the  organic  wastes 
of  the  kitchen ;  or,  finally,  the  fact  that  some  of  the  larg- 
est cities  in  the  world,  such  as  Berlin,  successfully  dispose 
of  all  their  sewage  by  simply  pouring  it  upon  the  land. 
There  is  every  reason  to  believe  that  this  method  of  sewage 
disposal,  which  is  successfully  in  operation  under  either 
natural  or  artificial  conditions  all  over  the  world,  is,  at  the 
same  time,  one  of  the  most  primitive,  one  of  the  most 
practical,  and  one  of  the  most  perfect,  systems  hitherto 
employed  by  man.  We  may,  therefore,  in  the  next  para- 
graphs, properly  devote  considerable  attention  to  its  theory 
and  practice.  By  a  curiously  unfortunate  use  of  words 
this  process  has  come  to  be  known  by  the  altogether 
inadequate  term  "intermittent  filtration."  As  we  shall 
now  see,  intermittent  filtration  lies  at  the  basis  of  all 
sewage  disposal  by  irrigation  and  of  all  successful  sewage- 
farming. 


LAND-DISPOSAL   OF   SEWAGE  137 

§  II.  —  Intermittent  Filtration 

^  In  all  cases  of  sewage  disposal  upon  land,  whether  crops 
be  grown  upon  the  land  or  not,  the  fundamental  processes 
at  work  are  those  involved  in  intermittent  nitration,  and 
this,  as  has  been  explained  in  the  preceding  paragraph, 
consists  in  biological  and  chemical  treatment  of,  or  reaction 
upon,  sewage  by  the  living  earth. 

It  has  long  been  known  that  earth  and  soil  are  remark- 
ably effective  in  the  purification  of  sewage.  Everyday 
observation,  such  as  that  described  in  the  preceding  section 
in  connection  with  the  ordinary  operations  of  agriculture, 
proves  that  land-disposal  of  organic  wastes  is  perfectly 
natural  and  successful.  The  process,  consisting  as  it  does 
in  a  change  of  organic  into  inorganic  matter,  early  attracted 
the  attention  of  chemists,  and  inasmuch  as  the  purification, 
chemically  speaking,  consists  largely  in  oxidation  of  nitroge- 
nous bodies  with  conversion  of  the  latter  into  nitrates,  the 
essential  phenomenon  is  often  described  as  "  nitrification." 

§  1 2.  —  English  Experiments  on  Intermittent  Filtration 

At  first  it  was  supposed  that  nitrification  was  due  to  the 
direct  action  of  the  oxygen  of  the  air  upon  complex  nitroge- 
nous bodies,  but  it  was  soon  perceived  that  something  more 
must  be  at  work.  It  was  evident,  for  instance,  that  stable 
manure  exposed  to  an  abundance  of  oxygen  in  the  air  re- 
mained unaffected,  while  if  it  were  brought  into  contact  with 
the  soil  in  the  ordinary  process  of  agriculture,  it  speedily 
disappeared,  giving  rise  to  nitrates  in  abundance.  Labora- 
tory experiments  showed  further  that  the  nitrification  could 
readily  be  set  up  by  introducing  earth  into  mixtures  which  it 
was  desired  to  nitrify,  so  that  it  seemed  perfectly  clear  that 
somehow  the  earth  possessed  a  specific,  nitrifying  power. 
Some  supposed  that  this  was  due  to  its  porous  character 
which  might  produce  oxidation  somewhat  after  the  fashion 
of  platinum  sponge. 


138  ON   SEWAGE  AND   ITS  PURIFICATION 

The  first  experiments  on  the  disposal  of  sewage  upon 
land  or  earth  were  laboratory  experiments  made  by  the 
Rivers  Pollution  Commissioners  of  Great  Britain  appointed 
in  1868,  in  connection  with  their  investigations  of  the  pollu- 
tion of  rivers,  and  were  most  instructive.  In  these  experi- 
ments, glass  tubes,  sixteen  feet  long  and  two  inches  in 
diameter,  and  glass  cylinders,  six  feet  long,  and  either  ten 
and  one-fourth  or  twelve  inches  in  diameter,  were  filled 
with  various  kinds  of  soil.  Each  then  received  at  the 
top  (or  in  some  cases  at  the  bottom)  known  amounts 
of  sewage  which  were  discharged  as  effluent  at  the 
other  end,  and  in  the  case  of  downward  intermittent  fil- 
tration were  found  to  have  been  remarkably  purified.  A 
full  report  of  these  important  investigations  may  be  found 
in  the  First  Report  of  the  Rivers  Pollution  Commission 
appointed  in  1868,  published  in  1870.  (Mersey  and 
Ribble  Basins,  Vol.  I,  pp.  60-70.)  The  facts  developed 
by  these  experiments  remained,  however,  largely  unex- 
plained until  a  few  years  later  when  the  investigations  of 
other  observers  drew  attention  to  the  probable  cooperation 
of  micro-organisms  in  the  processes  of  nitrification.  More- 
over, the  Commission's  experiments  were  conducted  on 
a  laboratory  scale,  and  were  limited  in  number  as  well  as 
in  time. 

§  13.  —  The  Problem  Attacked  in  Massachusetts 

It  remained  for  the  State  Board  of  Health  of  Massa- 
chusetts to  take  up  the  problem  where  the  Commission 
had  left  it,  and  to  make  for  the  first  time  extensive  and 
elaborate  experiments  upon  a  large  scale  with  the  aid  of 
bacteriology  as  well  as  chemistry,  upon  the  purification  of 
sewage  by  land  treatment  or  "intermittent  filtration."  In- 
asmuch as  these  investigations  were  the  first  to  be 
made  on  a  large  scale  and  for  a  long  time,  and  inasmuch 
as  they  have  now  become  classical,  we  may  describe 


EARLY  INVESTIGATIONS  IN  ENGLAND  139 

them,  together  with  the  conditions  which  led  up  to  them, 
in  some  detail.1 

The  state  of  Massachusetts,  especially  in  its  eastern 
portion,  had  become,  by  1880,  so  thickly  settled  that  the  dis- 
posal of  the  sewage  of  the  numerous  cities  and  towns  com- 
posing the  metropolitan  district  having  Boston  as  its  centre 
was  becoming  a  serious  problem.  Accordingly,  in  1881, 
a  Commission  was  appointed  to  consider  and  report  upon 
the  drainage  of  the  Mystic  and  Charles  River  valleys. 
The  report  of  these  commissioners  recommended  a  metro- 
politan district  system  which  should  preserve  as  far  as 
practicable  by  general  sewerage  the  purity  of  the  water 
supplies  of  the  cities  included  in  this  district.  In  1884  the 
Massachusetts  Drainage  Commission  was  appointed,  and 
hi  1886  their  report  was  published,  giving  a  large  amount 
of  valuable  information  regarding  sewage  disposal  theories 
and  practices  in  England  and  on  the  Continent.  Perhaps 
the  most  important  work  which  they  accomplished,  how- 
ever, was  their  earnest  recommendation  that  the  common- 
wealth of  Massachusetts  should  appoint  a  Commission  or 
designate  Guardians  to  conserve  the  purity  of  the  inland 
waters  of  the  state,  such  body  to  be  provided  with  advisory 
rather  than  mandatory  powers. 

"  Let  these  guardians  of  inland  waters  be  charged  to  acquaint  them- 
selves with  the  actual  condition  of  all  waters  within  the  state  as  respects 
their  pollution  or  purity,  and  to  inform  themselves  particularly  as  to  the 
relation  which  that  condition  bears  to  the  health  and  well-being  of  any 
part  of  the  people  of  the  commonwealth.  Let  them  do  away,  as  far  as 
possible,  with  all  remediable  pollution,  and  use  every  means  in  their 
power  to  prevent  further  vitiation.  Let  them  make  it  their  business  to 
advise  and  assist  cities  or  towns  desiring  a  supply  of  water  or  a  system 
of  sewerage.  They  shall  put  themselves  at  the  disposal  of  manufac- 
turers and  others  using  rivers,  streams,  or  ponds,  or  in  any  way  mis- 

1  For  an  interesting  and  valuable  historical  statement  of  the  rise  and  treat- 
ment of  the  drainage  problem  in  a  growing  community,  see  Report  of  a  Com- 
mission appointed  to  consider  a  General  System  of  Drainage  for  the  Valleys  of 
Mystic,  Blackstone,  and  Charles  Rivers.  Boston,  1886. 


140  ON   SEWAGE  AND   ITS   PURIFICATION 

using  them,  to  suggest  the  best  means  of  minimizing  the  amount  of  dirt 
in  their  effluent,  and  to  experiment  upon  methods  of  reducing  or  avoid- 
ing pollution.  They  shall  warn  the  persistent  violator  of  all  reasonable 
regulation  in  the  management  of  water,  of  the  consequences  of  his  acts. 
In  a  word,  it  shall  be  their  especial  function  to  guard  the  public  interest 
and  the  public  health  in  its  relation  with  water,  whether  pure  or  defiled, 
with  the  ultimate  hope,  which  must  never  be  abandoned,  that  sooner  or 
later  ways  may  be  found  to  redeem  and  preserve  all  the  waters  of  the 
State.  We  propose  to  clothe  the  board  with  no  other  power  than  the 
power  to  examine,  advise,  and  report,  except  in  cases  of  violation  of  the 
statutes.  Such  cases,  if  persisted  in  after  the  notice,  are  to  be  referred 
to  the  attorney  general  for  action.  Other  than  this,  its  decisions  must 
look  for  their  sanction  to  their  own  intrinsic  sense  and  soundness.  Its 
last  protest  against  wilful  and  obstinate  defilement  will  be  to  the  General 
Court.  To  that  tribunal  it  shall  report  all  the  facts,  leaving  to  its 
supreme  discretion  the  final  disposition  of  such  offenders." 1 

§  14.  —  Reorganization  of  the  State  Board  of  HealtJi  of 
Massachusetts 

The  legislature  of  1886  promptly  adopted  the  recommen- 
dation of  the  Drainage  Commission,  and  turned  to  the 
State  Board  of  Health  as  the  proper  body  to  undertake 
the  new  and  important  functions  which  it  was  proposed 
to  create.  The  Board  was  reconstituted  and  reorganized, 
and  endowed  not  only  with  the  usual  powers  and  duties 
of  a  State  Board  of  Health,  but  with  entirely  new  and 
peculiar  functions  in  regard  to  the  water  supplies  and 
sewerage  of  the  towns  and  cities  of  the  commonwealth. 
The  board  was  to  become  the  expert  sanitary  adviser  of 
the  towns,  and  a  fortiori  of  the  legislature,  in  these  particu- 
lars ;  and  it  was  to  be  liberally  supported.  As  a  special 
recognition  of  the  new  functions,  Mr.  Hiram  F.  Mills,  of 
Lawrence,  perhaps  the  most  distinguished  hydraulic  engi- 
neer within  the  state,  was  made  a  member  of  the  reorganized 
Board,  and  immediately  took  charge  of  the  experiments 
upon  intermittent  filtration. 

1  Massachusetts  Drainage  Commission  Report  (full  reference  given  above), 
p.  Ixi.  Boston,  1886. 


PROTECTION   OF   PURITY   OF   INLAND  WATERS     141 

The  statute  which  provided  the  new  functions  for  the 
Board  was  approved  on  June  9,  1886,  .and  was  entitled 
"  An  Act  to  protect  the  Purity  of  Inland  Waters."  In  sub- 
stance, and  to  a  large  extent  in  form,  it  corresponds  with 
one  recommended  by  the  Drainage  Commission.  It  has 
proved  to  be  one  of  the  most  novel  and  satisfactory  enact- 
ments for  the  benefit  of  the  public  health  ever  undertaken 
in  America.  In  one  important  respect  the  statute  actually 
adopted  differed  from  that  recommended,  namely,  in  pro- 
viding that  the  members  of  the  Board  should  serve  without 
pay.  The  special  functions  of  the  State  Board  of  Health 
as  laid  down  in  this  statue,  concisely  stated,  were  as  fol- 
lows :  — 

1.  To  have  the  general  care  and  oversight  of  all  the 
inland  waters  of  the  commonwealth. 

2.  To   recommend   legislation    and   suitable   plans   for 
systems  of  main  sewers  for  the  state. 

3.  To  cause  examinations  of  the  waters  of  ponds  and 
streams  to  be  made. 

4.  To  recommend  measures  to  prevent  the  pollution  of 
waters. 

5.  To  conduct  experiments  on  the  purification  of  drain- 
age. 

6.  To  conduct  experiments  on  the  disposal  of  manu- 
facturing refuse. 

7.  To  consult  with  and  advise  the  authorities  of  cities 
and  towns,  or  with  others,  with  reference  to  water  supply 
and  drainage. 

8.  To  consult  with  and  advise  manufacturers  with  refer- 
ence to  the  disposal  of  manufacturing  refuse. 

9.  To  bring  to  the  notice  of  the  attorney  general  all 
omissions  to  comply  with  existing  laws. 

The  act  further  provides  that  authorities  of  cities  and 
towns,  and  all  others  intending  to  introduce  systems  of 
water  supply  or  sewerage,  shall  submit  to  the  Board  out- 
lines of  their  proposed  plans  or  schemes  in  relation  to 


142  ON   SEWAGE   AND   ITS   PURIFICATION 

these  subjects ;  and  that  manufacturers  intending  to  en- 
gage in  any  business,  drainage  or  refuse  from  which  may 
tend  to  cause  the  pollution  of  any  inland  waters,  shall  also 
give  notice  to  the  Board  of  their  intentions.  The  Board 
immediately  proceeded  to  carry  out  the  provisions  of  the 
act,  and  in  its  first  report,  dated  January,  1887,  it  states 
in  extenso  precisely  what  it  proposes  to  do  if  adequately 
supported,  and  concludes  :  — 

"  In  order  to  make  the  series  of  examinations  above  out- 
lined, including  monthly  analyses  of  all  waters  used  for 
domestic  supply  in  the  state,  and  biological  examinations 
of  certain  waters  injuriously  affected  by  animal  life,  to- 
gether with  chemical  analyses  of  other  inland  waters ;  to 
conduct  contemplated  experiments  upon  the  purification  of 
sewage  and  refuse  from  industrial  establishments  ;  to  make 
the  necessary  investigations  in  order  to  advise  cities,  towns, 
corporations  and  individuals  in  regard  to  the  best  method 
of  disposing  of  their  sewage ;  and  to  carry  out  the  other 
provisions  of  Chapter  274, — the  board  estimates  that  the 
sum  of  $30,000  [for  the  first  year]  will  be  required." 

§  15.  —  The  Lawrence  Experiment  Station  of  the  State 
Board  of  Health  of  Massachusetts. 

The  commonwealth  cheerfully  did  its  part,  the  legisla- 
ture granting  the  large  sum  asked  for  by  the  Board  which 
thereupon  proceeded  to  complete  its  organization  for  work 
along  the  lines  indicated.  It  announced  that  it  was  ready 
to  consult  with  and  give  advice  to  any  Massachusetts  city 
or  town  concerning  its  water  supply  or  sewerage.  At  the 
same  time  it  was  distinctly  held  by  the  Board  that,  in  order 
to  give  adequate  and  really  expert  advice,  it  must  experi- 
ment and  investigate.  It  was  not  to  rest  content  with  the 
scanty  or  imperfect  knowledge  of  these  subjects  which  was 
too  often  all  that  was  available,  or  to  accept  without  trial 
the  methods  or  the  results  of  scattered  or  local  observers ; 


A   SANITARY   EXPERIMENT   STATION  143 

but,  first,  to  investigate  for  itself  the  actual  condition  of  the 
various  water  supplies  of  the  state  by  all  means  in  its 
power,  whether  engineering,  chemical  or  biological;  and, 
second,  after  having  obtained  all  available  information  at 
home  and  abroad,  to  establish  an  experiment  station,  and 
make  for  itself  investigations  upon  the  long  vexed  ques- 
tions of  the  purification  of  sewage  and  drinking  water. 

This  station,  the  Lawrence  Experiment  Station,  the  first 
of  the  kind  in  America,  if  not  in  the  world,  was  located  in 
a  building  adapted  for  the  purpose,  which  had  been  con- 
structed upon  land  on  the  left  bank  of  the  Merrimac  River, 
belonging  to  the  Essex  Company  and  already  used  at  an 
earlier  date  by  Mr.  Mills  for  experiments  in  hydraulics. 

§  1 6.  —  The  Massachusetts  Experiments  at  Lawrence 

The  first  problem  attacked  at  the  Lawrence  Experiment 
Station  was  that  of  the  best  method  for  the  disposal  of 
sewage  upon  land.  English  and  German  experience  had 
made  it  probable  that  much  might  be  done  in  this  direction 
in  America ;  but  the  knowledge  available  was  very  limited 
and  of  little  or  no  practical  value  to  American  engineers, 
because  the  climates,  soils,  sewages,  and  civil  and  eco- 
nomic conditions  of  America  are  so  different  from  those  of 
Europe.  Accordingly,  in  November,  1887,  a  series  of 
careful  experiments  was  begun,  to  test  the  purifying  capac- 
ity of  various  soils  and  sands  occurring  in  Massachusetts. 

For  this  purpose,  a  number  of  large  wooden  tubs  or  tanks 
built  of  cypress  were  cautiously  filled  with  different  soils, 
ranging  from  muck  and  garden  loam  on  the  one  hand, 
through  fine  sand  and  coarse  sand  to  mixed  gravel  stones, 
coarser  materials,  and  pebbles  on  the  other.  The  soil  or 
sand  to  be  tested  was  in  each  case  supported  by  a  stratum 
of  stones  and  gravel,  and  underdrained  through  an  effluent 
pipe  which  emptied  into  a  large  measuring  basin.  The 
sewage  was  also  measured  as  it  flowed  on  at  the  top,  and 


144  ON   SEWAGE  AND   ITS  PURIFICATION 

the  whole  experiment  was  under  control  in  every  respect. 
Each  tank,  or  "  filter,"  was  sixteen  feet  in  diameter,  or  one 
two-hundredth  of  an  acre  in  area,  and  the  filtering  material 
in  each  case  was  five  feet  in  depth.  The  sewage  to  be  ex- 
perimented with  was  drawn  from  one  of  the  main  sewers 
of  the  city  of  Lawrence,  and  was  ordinary  domestic  city 
sewage,  free  from  manufacturing  wastes.  No  experiments 
of  this  kind  had  ever  before  been  undertaken  on  such  a 
scale  or  with  so  much  care.  For  the  first  time  in  the  his- 
tory of  science,  engineers,  chemists  and  biologists  worked 
together  under  the  direction  of  a  master  in  hydraulics, 
toward  one  common  end,  —  the  promotion  of  the  public 
health. 

The  results  crowned  the  endeavor.  Intelligent  by-stand- 
ers,  who  saw  the  sewage  flowing  upon  the  filters,  at  the  out- 
set unhesitatingly  predicted  failure.  They  felt  certain,  and 
did  not  hesitate  to  express  their  belief,  that  in  a  fortnight,  at 
the  latest,  the  filters  would  become  clogged  and  foul,  and  the 
whole  neighborhood  pestilential.  They  did  not  know  that 
Berlin,  the  German  capital,  disposes  of  all  its  sewage  upon 
land.  They  forgot  that  the  farmer  once  a  year,  or  oftener, 
manures  his  fields  with  filth,  and  that  the  hungry  earth  re- 
ceives the  gift  with  open  mouth,  devours  it,  and  soon  cries 
out  for  more.  As  soon  as  a  few  days  had  passed,  and  the 
filters  had  become  established,  the  effluent  began  to  grow 
bright  and  clear.  Chemical  analyses  showed  that  the 
out-put  was  now  purified  sewage,  comparatively  free  from 
odor,  and  poor  in  organic  matters.  Bacterial  analyses 
showed  that  while  earlier,  as  sewage,  it  was  swarming  with 
the  germs  of  putrefaction  and  decay,  it  now  contained  only 
a  few  bacteria.  Further  studies  revealed  the  fact  that 
the  foulness  of  the  sewage  was  not  held  back  as  by  a 
strainer ;  but  rather  that  as  wood  by  a  slow  fire  is  turned  to 
ashes,  the  organic  matters  here  were  slowly  reduced  to  min- 
eral substances.  No  disagreeable  odor  developed,  and  the 
filters  showed  no  signs  of  clogging.  Thus  the  very  name 


THE   MASSACHUSETTS   EXPERIMENTS  145 

"filter"  became  a  misnomer.  The  by-standers  were 
amazed,  and  could  not  repress  their  feelings  of  surprise  and 
admiration. 


§  17.  —  Anatomy  and  Physiology  of  Intermittent  Filters 

Meanwhile  the  data  of  the  experiments  were  accumulat- 
ing. Winter  came  on,  and  still  the  "  filters "  did  their 
work.  Already  it  was  proved  that  land-disposal  of  sewage 
was  possible  for  America.  But,  curiously  enough,  those 
soils  —  such  as  muck  and  garden  loam  —  which  many  had 
predicted  would  be  the  most  useful,  proved  to  be  the  least 
effective.  They  were  too  close  in  texture,  too  fine,  too  im- 
pervious ;  while  sand  (such  as  ordinary  mortar  sand)  or 
even  fine  gravel  proved  to  be  the  most  effective.  And,  on 
looking  into  the  reason  why,  it  was  soon  perceived  that  the 
whole  process  is  a  vital  one.  The  soils  are  not  mere 
strainers,  for  at  the  very  outset  they  fail  to  work.  They  are 
rather  like  the  living  sponge,  —  an  animal  whose  body  is 
everywhere  channelled  with  fine  passages  lined  with  living 
cells.  The  fine  passages  in  the  body  of  the  filters  are 
the  spaces  between  the  sand  grains;  the  living  cells  are 
the  micro-organisms  which,  after  a  few  days,  come  to  dwell 
upon  the  sand  grains  and  line  the  passages.  And  very  much 
as  the  living  cells  of  a  sponge  detain  and  destroy  the  or- 
ganic particles  passing  by  them,  the  bacteria  resident  upon 
the  sand  grains  detain  and  work  over  the  organic  matters 
of  the  sewage  poured  upon  the  filter.  Again,  exactly  as  the 
living  organisms  of  which  a  sponge  is  essentially  composed 
require  oxygen  to  support  their  respiration,  so  those  inhabit- 
ing a  filter  must  have  abundant  air.  This  means  that  the 
sewage,  which  is  usually  destitute  of  oxygen,  must  not  be 
applied  continuously,  but  intermittently,  so  that  air  may 
follow  it  down  through  the  filter  and  keep  from  suffoca- 
tion the  purifying  micro-organisms.  And  this  also  explains 
why  intermittent  downward  filtration,  under  the  right  con- 


146  ON   SEWAGE  AND   ITS  PURIFICATION 

ditions,  is  always  successful,  while  continuous  nitration,  or 
upward  intermittent  nitration,  of  sewage  inevitably  fails. 

With  the  main  principles  once  established,  it  remained 
only  to  learn  the  details  of  their  application.  Sand  proved 
better  than  loam,  because  it  allowed  better  ventilation. 
Fine  sand  proved  better  than  coarse  sand,  because  it  seems 
to  be  the  happy  mean,  giving  full  exposure  to  the  air  by 
distributing  the  sewage  in  thin  films  over  a  vast  number 
of  surfaces,  but  yet  allowing  sufficient  ventilation. 

The  practical  results  were  quick  to  follow.  Once  the 
purifying  values  of  sands  of  particular  sizes  were  estab- 
lished, it  remained  only  to  obtain  samples  of  sand  from  any 
town  desiring  to  dispose  of  its  sewage  on  land,  and  to  ex- 
amine and  compare  them  with  known  sands,  to  be  able  to 
predict  for  that  community  either  success  or  failure.  The 
town  of  Framingham  soon 'constructed  a  large  municipal 
filter  under  the  advice  of  the  Board,  and  it  has  proved  an 
unqualified  success.  The  city  of  Brockton  soon  after  fol- 
lowed suit,  and  built  an  admirable  system  of  intermittent 
sand  filters  for  the  disposal  of  its  sewage.  Henceforward 
any  city  or  town  —  not  only  in  Massachusetts,  but  in 
America,  or  in  the  world  —  may,  if  its  soil  be  right,  and 
other  conditions  favorable,  adopt,  with  perfect  confidence, 
systems  for  the  land-disposal  of  sewage. 

§  1 8.  —  Theoretical  Aspects  of  Intermittent  Filtration 

Enough  has  now  been  said  to  make  it  clear  that  inter- 
mittent filtration  is  not  really  filtration  at  all,  in  the  etymo- 
logical sense,  but  rather  a  biological  and  chemical  process 
of  extreme  delicacy.  A  field  of  sandy  soil  may,  it  is  true, 
be  a  very  effective  strainer ;  but  if  worked  intermittently, 
it  is  much  more  than  this.  A  mere  strainer  soon  chokes, 
and  must  be  cleaned;  but  an  intermittent  filter  does  not 
readily  choke,  and  is  largely  self-cleaning.  This  is  a  phe- 
nomenon which  can  be  actually  witnessed.  When  sewage 


THEORY  OF   INTERMITTENT  FILTRATION         147 

began  to  be  applied  to  the  several  tanks  outside  the  Law- 
rence Experiment  Station,  even  the  most  intelligent  of  the 
workmen  predicted  that  the  filters  would  soon  choke  and 
become  a  nuisance ;  but  after  two  years  of  actual  operation, 
hardly  anything  more  remarkable  or  objectionable  could  be 
seen  upon  them  than  upon  other  fertile  land.  This  simple 
ocular  demonstration  was  confirmed  by  the  results  of  analy- 
sis, and  the  mechanical  theory  is  readily  disproved  by  a  com- 
parison of  the  chemical  composition  of  the  effluent  with  that 
of  the  affluent.  In  the  life-history  of  an  intermittent  filter 
there  is  usually  a  period  at  the  outset  when  there  is  but 
little,  if  anything,  more  than  a  mechanical  purification  ;  but 
under  the  best  conditions  there  speedily  begins  a  change  of 
the  profoundest  significance.  The  dissolved  organic  mat- 
ters no  longer  pass  out  as  they  came  in ;  the  suspended 
matters  for  the  most  part  cease  to  accumulate ;  and  both 
appear  in  the  effluent  under  other  forms.  Obviously,  me- 
chanical processes  alone  could  not  effect  such  changes ; 
and  besides,  these  changes  may  occur  under  conditions 
which  exclude  entirely  the  purely  mechanical  hypothesis. 
A  most  striking  example  of  this  kind  is  to  be  found  in  the 
operation  of  a  tank  composed  of  small  stones,  the  spaces 
between  which  are,  as  compared  with  much  of  the  organic 
matter  of  sewage,  of  infinitely  large  size ;  yet  the  changes 
wrought  by  this  filter  are  far  more  extensive,  and  the  purifi- 
cation is  far  more  complete,  than  in  filters  of  peat  or  garden 
soil,  which  are  mechanically  nearly  perfect  strainers.  It 
would  be  hard  to  find  a  better  example  of  the  possibilities 
of  sewage  filtration  than  such  a  tank  supplies;  yet  this 
filter  testifies  in  the  clearest  manner  to  the  absolute  insig- 
nificance of  any  merely  mechanical  factor  in  the  purifica- 
tion of  sewage  by  intermittent  filtration. 

§  19.  —  Intermittent  Filtration  a  Biological  Process 

A  theory  much  more  reasonable  than  the  mechanical 
hypothesis  is  that  the  action  of  an  intermittent  filter  is 


148  ON    SEWAGE   AND   ITS   PURIFICATION 

fundamentally  chemical.  Of  the  powers  of  intermittent 
filters  to  effect  chemical  changes  there  is  no  question,  as 
the  previous  pages  of  this  chapter  abundantly  testify. 
Moreover,  the  transformations  effected  are  so  thorough 
that  the  analogy  of  purification  by  fire  must  occur  to  every 
thoughtful  observer.  Very  early,  however,  the  existence  of 
an  additional  factor  began  to  be  recognized.  Thus  the 
Rivers  Pollution  Commission  in  their  experiments  on  inter- 
mittent filtration,  although  insisting  upon  the  chemical 
character  of  the  purification  obtained,  referred  to  the  pro- 
cess as  an  act  of  respiration,  adding,  most  unconsciously, 
the  vital  to  the  purely  chemical  idea :  "  From  all  of  these 
experiments,  then,  it  appears  that  the  action  of  the  filter 
must  not  be  considered  as  merely  mechanical.  The  process 
carried  on  in  it  is  also  chemical.  ...  A  field  of  porous 
soil  irrigated  intermittently,  virtually  performs  an  act  of 
respiration."  (Cf.  p.  150.) 

It  has  since  been  definitely  established,  moreover,  that 
micro-organisms  are  an  indispensable  element  in  the  con- 
stitution of  a  successful  intermittent  filter,  so  that  the 
essentially  chemical  theory  has  given  place  to  one  essen- 
tially vital,  or  biological. 

"  Upon  the  biological  theory,  an  intermittent  filter  is  no 
longer  regarded  as  a  mechanical  strainer,  nor  is  it  merely  a 
chemical  furnace;  it  resembles  a  living  organism."  1 

§  20.  —  Objections  to  Intermittent  Filtration 

The  Rivers  Pollution  Commissioners'  a  priori  criticisms 
of  the  practical  value  of  intermittent  filtration  are  worthy 
of  note  as  we  bring  this  section  to  a  close :  — 

"  Nevertheless  there  are  three  formidable  objections  to  the  general 
adoption  of  this  process  :  first,  it  is  entirely  unremunerative.  the  amount 
of  sewage  applied  to  a  given  acre  of  land  being  probably  in  such  a  case 

1  Experimental  Investigations  by  the  State  Board  of  Health  of  Massachusetts 
upon  the  Purification  of  Sewage  by  Filtration,  etc.  p.  861.  Boston,  1890. 


INTERMITTENT  FILTRATION  NOT  REMUNERATIVE     149 

too  great  to  permit  of  the  growth  of  any  ordinary  agricultural  crop ; 
second,  the  whole  of  the  manure  ingredients  of  the  sewage  would  be 
absolutely  wasted ;  and  third,  the  collection  of  solid  faecal  matters  upon 
the  surface  of  the  soil,  with  no  vegetation  to  make  use  of  them,  would 
probably  give  rise  to  a  formidable  nuisance,  especially  in  hot  weather. 
We  also  entertain  doubts  as  to  the  process  being  equally  successful  under 
ordinary  management  on  a  large  scale,  since  the  sewage  would  be  likely 
to  pass  through  the  land  in  an  unequal  manner  —  in  some  places  reach- 
ing the  drains  very  rapidly,  in  others  passing  through  the  soil  too 
slowly.  .  .  .  Filtration,  properly  conducted,  results  in  the  oxidation, 
and  transformation  of  offensive  organic  substances  in  solution,  as 
well  as  in  the  mere  mechanical  separation  of  the  suspended  solid 
matters  which,  when  in  motion,  sewage  conveys  with  it.  If  the  process 
could  be  carried  one  step  farther,  and  £hose  harmless  inorganic  salts, 
which  are  carried  off  by  the  effluent  water  of  a  perfect  sewage  filter  in 
too  dilute  a  solution  to  be  profitably  extracted,  could  be  converted  into 
something  positively  useful,  the  remedy  would  be  complete.  We  should 
have  succeeded  in  not  only  abating  an  injurious  nuisance,  but  in  realizing 
a  product  which  would  help  to  refund  expenses.  This  further  step  is 
possible  in  the  great  majority  of  cases ;  and  it  is  to  the  plan  of  using 
sewage  in  irrigation,  as  being  in  reality  a  filtration  of  the  best  kind,  plus 
a  conversion  of  its  filthy  contents  into  valuable  products,  that  we  have 
now  to  direct  attention."  —  Rivers  Pollution  Commission  of  1868,  Re- 
port, Part  I,  p.  70.  London,  1870. 

The  objections  here  raised  that  the  process  is  unremu- 
nerative  and  that  the  end  products  are  wasted,  still  hold ; 
but  the  fear  that  a  nuisance  must  result  from  the  accumu- 
lation of  matters  on  the  surface  of  fields  devoted  to  inter- 
mittent nitration,  has  been  shown  by  experience  to  be 
groundless.  We  may  now  follow  the  line  of  thought 
laid  down  by  the  commissioners,  and  pass  on  to  a  con- 
sideration of  sewage  disposal  by  irrigation. 

§21.  —  Disposal  and  Purification  of  Sewage  by  Irrigation 

In  the  second  report  of  the  Commissioners  appointed  in 
1868  to  inquire  into  the  best  means  of  preventing  the  pol- 
lution of  rivers  ("  Mersey  and  Kibble  Basins  "),  p.  19,  sew- 
age irrigation  is  referred  to  as  a  process  — 


150  ON   SEWAGE   AND   ITS   PURIFICATION 

"where  sewage  has  been  submitted,  by  means  of  irrigation,  to  the 
action  of  a  vast  mass  of  soil  whose  surface  is  covered  with  growing 
plants,  which  it  feeds,  whose  depth  is  penetrated  by  their  hungry  roots, 
and  whose  whole  substance  provides  an  immense  quantity  of  material 
efficient  for  sewage  defalcation.  .  .  . 

"  If  we  except  the  laboratory  experiments  in  the  treatment  of  sewage 
in  the  intermittent  downward  filtration  described  in  our  first  report  .  .  . 
no  other  method  of  sewage  defalcation  approaches  irrigation  in  the 
uniform  excellence  of  its  results.  It  is  no  doubt  very  desirable,  in  the 
interest  of  those  towns  where  sewage  cannot  be  dealt  with  by  irrigation, 
that  an  experiment  in  intermittent  downward  filtration  should  be  con- 
ducted on  what  may  be  considered  a  working  scale,  —  when  all  those 
difficulties  would  arise  which  do  not  show  themselves  in  a  laboratory 
experiment,  and  when  it  would  be  proved  whether  the  process  can  be 
conducted  on  the  drainage  water  of,  say,  20,000  people  with  the  efficiency 
to  which  our  laboratory  experiments  pointed,  and  without  creating  a 
nuisance.  But  the  best  result  under  that  system  would  simply  be  the 
conversion  of  a  polluting  into  a  non-polluting  stream.  The  injury  done 
by  town  sewage  would  in  that  case  disappear,  but  the  agricultural  value 
of  it  would  be  wholly  lost.  By  using  it  in  irrigation,  on  the  other  hand, 
the  nuisance  vanishes,  while  the  fertilizing  influence  is  retained  and 
utilized." 

In  the  first  report  of  the  Commissioners,  to  which  refer- 
ence has  already  been  made  in  the  preceding  section, 
the  purification  of  sewage  by  irrigation  is  well  described 
as  follows  (Vol.  I,  p.  70) :  — 

"  We  have  still  to  discuss  what  may  be  called  the  agricultural  remedy 
for  the  nuisance  created  by  town  sewage.  In  the  first  place,  irrigation 
involves  filtration.  .  .  .  But  a  filter,  as  has  been  already  shown,  is  not 
a  mere  mechanical  contrivance.  It  is  a  machine  for  oxidizing,  and  thus 
altogether  transforming  as  well  as  for  merely  separating  the  filth  of  dirty 
water.  And  in  this  respect  especially,  irrigation  necessarily  includes 
filtration.  Sewage  traversing  the  soil  undergoes  a  process  to  some 
extent  analogous  to  that  experienced  by  blood  passing  through  the 
lungs  in  the  act  of  breathing.  A  field  of  porous  soil  irrigated  inter- 
mittently virtually  performs  an  act  of  respiration,  copying  on  an  enor- 
mous scale  the  lung  action  of  a  breathing  animal ;  for  it  is  alternately 
receiving  and  expiring  air,  and  thus  dealing  as  an  oxidizing  agent  with 
the  filthy  fluid  which  is  trickling  through  it.  And  a  whole  acre  of  soil 
three  or  four  feet  deep,  presenting  within  it  such  an  enormous  lung  sur- 
face, must  be  far  superior  as  an  oxidizer  for  dealing  with  the  drainage 


SEWAGE   DISPOSAL   BY   IRRIGATION  151 

of  one  hundred  people,  to  any  filter  that  could  be  practically  worked  for 
this  purpose. 

"  To  this  item  in  the  character  of  both  irrigation  and  filtration  as 
chemical  processes,  there  must  be  added  another  cleansing  agency  also 
of  a  chemical  kind,  in  which  the  former  has  very  greatly  the  advantage. 
We  refer  to  the  actual  appetite  for  certain  dissolved  impurities  in  filthy 
water,  which  soil,  whether  in  a  tank  or  covering  a  field,  owes  both  to 
general  surface  attraction  and  to  the  chemical  affinities  which  some  of 
its  ingredients  possess.  This  appetite  is  doubtless  very  limited  in  its 
amount,  but  it  is  directly  proportional  to  the  quantity  of  material  exer- 
cising it.  The  superior  capability  of  this  kind  which  the  soil  of  a  field 
possesses,  in  comparison  with  that  in  a  limited  filtration  tank,  depends 
partly  on  the  immensely  greater  quantity  of  cleansing  material  which  an 
acre  drained  perhaps  four  feet  deep  necessarily  brings  to  bear  upon  the 
filthy  fluid ;  but  also  and  especially  on  the  fact  that  in  the  former  case 
this  appetite  is,  except  in  winter  time,  always  kept  alive  and  fresh  by 
the  action  of  plant  growth  in  constantly  removing  the  deposited  impuri- 
ties, and  rebuilding  them  into  wholesome  organic  structures. 

"  Considered  then  merely  as  a  mechanical  and  chemical  agency  for 
cleansing  the  drainage  water  of  our  towns,  it  seems  plain  that  a  sufficient 
extent  and  depth  of  porous  soil  to  be  used  in  irrigation,  having  peri- 
odical intervals  of  rest,  during  which  the  soil  drains  and  becomes  refilled 
with  air,  certainly  must  be  the  best  possible  strainer,  oxidizer,  and  filter 
of  water  which,  like  the  sewer  water  of  our  towns,  contains  nauseous 
organic  impurities,  both  suspended  and  dissolved.  That  it  is  so, 
analyses  of  effluent  waters  have  satisfactorily  proved,  as  will  be  illus- 
trated at  length  hereafter.  Meanwhile  we  have  further  to  consider  the 
last  great  advantage  of  the  soil  over  all  other  filters,  in  that  it  utilizes  a 
considerable  proportion  of  the  substances  which  they  only  separate,  or 
at  best  transform. 

"  This  is  the  second  point  in  our  discussion  of  the  agricultural 
remedy  for  river  pollution,  so  far  as  that  is  due  to  the  influx  of  town 
sewage.  Sewage  filth  is  '  fertilizing  matter,'  and  therefore  valuable  as 
a  manure.  Every  one  is  familiar  with  the  idea  that  the  fertility  of  a 
farm  depends  very  much  on  the  quantity  of  the  live  stock  kept  upon  it. 
It  is,  in  fact,  an  established  maxim  in  agriculture  that,  apart  from  the 
use  of  imported  and  manufactured  fertilizers,  the  maintenance  of  fertility 
depends  very  much  upon  the  live  stock  which  the  farmer  keeps  upon 
the  land,  and  the  quantity  of  manure  which  he  can  thus  apply  to 
it 

"The  process  of  filtration  through  sand,  gravel,  chalk,  or  certain 
kinds  of  soil  if  properly  carried  out  is  the  most  effective  means  for  the 
purification  of  sewage  to  which  reference  has  yet  been  made ;  indeed, 


152  ON   SEWAGE   AND   ITS   PURIFICATION 

irrigation,  as  now  carried  out,  owes  no  inconsiderable  amount  of  its 
success  to  the  contemporaneous  effect  of  the  filtration  of  the  sewage 
through  the  soil  of  the  irrigated  fields  ;  for  it  is  precisely  in  those  cases 
in  which  the  sewage  is  absorbed  and  disappears  in  porous  land,  that 
we  have  observed,  in  the  effluent  water  from  drains,  the  most  complete 
purifying  effect."  —  First  Report,  Rivers  Pollution  Commission  of  1 886, 
p.  60. 

§  22.  —  Sewage  Farms.     Objections  to  Sewage  Disposal  by 
Irrigation  and  Sewage  Farming 

The  disposal  of  sewage  by  means  of  irrigation  naturally 
involves  the  establishment  of  sewage  farms,  that  is,  a 
special  kind  of  farming  in  which  a  liquid  fertilizer  is 
supplied  in  abundance,  sometimes  in  superabundance. 
Enough  has  already  been  said  in  the  preceding  sections 
to  show  the  theoretical  importance  and  value  of  sewage 
as  a  fertilizer.  It  cannot  be  denied  that  sewage  possesses 
elements  of  large  fertilizing  value,  and  it  should  never  be 
forgotten  that  it  may  at  some  time  be  made  a  far  more 
powerful  aid  than  it  is  to-day  in  increasing  the  food  supply 
of  mankind. 

On  the  other  hand,  there  is  good  reason  to  believe  that 
the  practical  value  of  sewage  as  a  fertilizer  falls  far  below 
its  theoretical  value,  owing  chiefly  to  its  enormous  dilution  ; 
and  that  any  combination  of  farming  with  sewage  disposal 
is,  closely  examined,  of  doubtful  economic  wisdom,  at  least 
at  present,  in  America.  It  does  not  by  any  means  follow 
that,  because  sewage  contains  valuable  fertilizing  elements, 
it  is  therefore  wise  for  every  city  and  town  having  sewage 
to  dispose  of  to  undertake  sewage  farming.  It  must  be 
borne  in  mind  that  the  civilized  world  appears  to  have  been 
everywhere,  within  the  last  decade,  suffering  from  a  period  of 
agricultural  depression  due,  no  doubt,  in  great  part,  to  the 
vast  modern  improvements  in  agricultural  machinery,  and 
especially  to  the  wonderful  modern  facilities  for  trans- 
portation, which  allow  food  to  be  carried  from  almost  any 
point  of  supply  or  superabundance  to  points  where  it  is 


SEWAGE  FARMS  AND   SEWAGE   FARMING         153 

in  demand,  with  extraordinary  speed  and  cheapness;  and 
probably  also  to  the  remarkable  advances  which  have  been 
made  in  the  arts  of  food-preserving,  by  means  of  which  the 
superabundance  of  one  season  or  place  which  was  formerly 
wasted  by  decay  may  be  conserved  with  success  indefinitely, 
or  until  needed  either  there  or  at  some  remote  point  of  the 
earth's  surface.  It  is  hardly  necessary,  therefore,  in  a  period 
of  depression  in  agriculture,  such  as  has  lately  fallen  upon 
much  of  the  civilized  world,  to  undertake  agricultural  opera- 
tions at  a  loss,  and  it  is  not  surprising  that  objections  to 
sewage  farms  have  already  arisen  in  some  quarters  from 
farmers  who  are  obliged  to  compete  with  sewage  farming. 
There  can  be  no  doubt  that  a  greater  area  of  land  is  re- 
quired for  successful  sewage  disposal  by  sewage  farms, 
than  by  mere  intermittent  filtration,  and  it  is  of  very  dubi- 
ous wisdom,  at  least  in  the  United  States  where  land 
in  the  neighborhood  of  cities  is  dear,  where  municipal 
servants  are  likely  to  be  highly  paid,  and  where,  also,  agri- 
cultural produce  is  cheap,  to  undertake  sewage  farming 
either  for  economic  or  aesthetic  reasons.  Moreover,  as 
has  already  been  suggested,  there  are  other  objections 
than  the  purely  economic.  Quite  recently  it  was  found 
somewhat  difficult  for  the  city  of  Paris  to  secure  the  privi- 
lege of  adding  to  the  area  of  its  sewage  fields  because  of 
the  formidable  opposition  of  the  ordinary  farming  interests, 
which  alleged  with  considerable  vehemence  that  it  was  diffi- 
cult for  them,  unprovided  as  they  were  with  sewage  as  a 
fertilizer,  to  compete  successfully  with  the  sewage  farms 
already  in  existence,  upon  which  larger  crops  could  be 
more  cheaply  produced. 

There  is  also  the  sanitary  objection,  the  force  of  which 
must  to  some  extent  be  admitted,  that  vegetables  and  small 
fruits  grown  upon  sewage  fields  and  presumably  watered 
with  sewage  are  liable  to  become  contaminated  with  infec- 
tious materials.  We  must  probably  allow  that  lettuce, 
cabbages,  radishes,  strawberries  and  similar  vegetables 


154  ON   SEWAGE  AND   ITS   PURIFICATION 

or  fruits,  if  so  watered  or  flooded,  may  possibly  become 
thus  contaminated.  On  the  other  hand,  the  testimony  of 
vital  statistics  in  towns  and  cities  in  which  such  vegetables 
or  fruits  are  consumed  appears  to  be  distinctly  reassuring, 
and  the  advocates  of  sewage  farming  assert  with  much 
positiveness,  that  little  or  no  apprehension  need  be  felt  in 
this  direction.  Probably  the  truth  is  that,  in  some  countries 
very  often,  and  in  all  countries  in  some  cases,  the  disposal 
of  sewage  by  irrigation  is  the  most  suitable  method  to  be 
employed  or  recommended ;  but  that  in  America,  at  least 
for  the  present,  for  the  reasons  stated  above,  or  for  other 
reasons  peculiar  to  each  locality,  if  land  treatment  of  any 
kind  is  desirable  or  necessary,  intermittent  nitration  is  pref- 
erable. 

§  23.  —  The  Partial  Purification  of  Sewage  by  Chemical 
Precipitation 

In  the  first  report  of  the  Commissioners  appointed  in 
1868  to  inquire  into  the  best  means  of  the  preventing  the 
pollution  of  rivers  ("  Mersey  and  Ribble  Basins  "),  Vol.  I, 
p.  51,  1870,  the  Commissioners  introduce  their  discussion 
of  this  subject  as  follows  :  — 

"  The  cleansing  of  sewage  has  engaged  the  attention  of  many  chem- 
ists and  others  during  the  past  ten  or  fifteen  years ;  and  various  plans, 
some  exhibiting  great  merit  and  ingenuity,  have  been  proposed  for 
dealing  with  the  offensive  liquid.  .  .  .  The  valuable  constituents  of 
sewage  present  to  the  chemist  a  mine  of  wealth,  which  despite  so  many 
failures  has  constantly  stimulated  him  to  renewed  efforts  for  their 
extraction  in  a  portable  and  consequently  marketable  form. 

"The  chief  valuable  ingredients  of  sewage  are,  1st,  the  different 
forms  of  combined  nitrogen,  and  2d,  phosphoric  acid.  The  money 
value  of  these  constituents  dissolved  in  one  hundred  tons  of  average 
sewage  is  about  fifteen  shillings,  whilst  the  suspended  matters  contain 
only  about  two  shillings'  worth  of  them. 

"  There  is  but  little  difficulty  in  extracting  the  suspended  matters  by 
filtration,  but  as  these  do  not  contain  quite  one-seventh  of  the  total 
valuable  constituents,  the  process,  though  simple,  has  never  been  re- 
munerative ;  and  inasmuch  as  it  still  leaves  much  putrescible  organic 


SEWAGE  DISPOSAL  BY  CHEMICAL  PRECIPITATION     155 

matter  in  solution,  the  mere  extraction  of  the  suspended  matters  of 
sewage,  although  doubtless  tending  to  mitigate  nuisance,  does  not  pro- 
duce any  substantial  diminution  of  the  polluting  quality  of  the  liquid. 
The  operations  of  the  chemist  have,  therefore,  been  directed  chiefly  to 
the  soluble  constituents  of  sewage;  and  have  had  for  their  object 
either  the  precipitation  in  a  solid  form  of  the  valuable,  but  offensive, 
ingredients,  so  as  to  convert  them  into  portable  manure,  Gf,  secondly, 
the  rendering  them  inoffensive  by  the  action  of  disinfectants/  Although 
these  operations  have  not  been  altogether  unsuccessful,  they  have 
hitherto  entirely  failed  in  purifying  average  sewage  to  such  an  extent 
as  to  render  it  admissible  into  running  water.  We  have  formed  this 
opinion  both  from  observations  of  the  polluting  effect  of  such  chemi- 
cally purified  sewage  upon  the  streams  into  which  it  was  admitted,  and 
from  the  amount  of  putrescible  organic  matter  revealed  by  the  chemical 
analyses  of  the  sewage  after  treatment. 

"  It  would  obviously  be  rash  to  set  any  bounds  to  the  possibilities  of 
chemistry.  Substances  may,  perhaps,  be  hereafter  discovered  capable 
of  combining  with  and  rendering  insoluble  the  filthy  constituents  of  our 
town  drainage ;  but  we  are  compelled  to  admit  that  the  present  re- 
sources of  this  science  hold  out  no  hope  that  the  foul  matters  dissolved 
in  sewage  will  be  precipitated  and  got  rid  of  by  the  application  of 
chemicals  to  the  offensive  liquid.  The  chemical  affinities  of  these  foul 
matters  are  so  feeble,  and  the  matters  themselves  are  dissolved  in  such 
enormous  volumes  of  water,  that  their  precipitation  is  a  problem  of 
extreme  difficulty."  —  Second  Report,  Rivers  Pollution  Commission  of 
1868,  pp.  18,  19.  London,  1870. 

These  conclusions  may  fairly  be  taken  as  representative 
of  the  best  expert  opinion  thirty  years  ago.  In  the  mean- 
time all  attempts  to  make  the  chemical  precipitation  of 
sewage  a  source  of  pecuniary  profit  have  been  unsuccess- 
ful, and  the  most  that  is  hoped  for  to-day  is  to  keep  the 
expense  of  the  process  within  tolerable  bounds.  On  the 
other  hand,  the  sanitary  results  now  obtained  are  decidedly 
better  than  those  reported  by  the  Rivers  Pollution  Com- 
missioners in  the  quotations  given  above. 

This  method  of  sewage  disposal  is  much  used  in  Eng- 
land, either  alone  or  in  combination  with  disposal  of  the 
effluent  by  intermittent  nitration  or  irrigation.  The  efflu- 
ent is  usually  well  clarified,  and  shows  a  removal  of  about 
nine-tenths  of  the  suspended  matters  and  one-half  of  the 


156  ON   SEWAGE   AND   ITS   PURIFICATION 

total  organic  matters.  Experience  has  shown  that  such  an 
effluent  can  safely  be  admitted  into  a  stream  of  relatively 
large  size,  provided  it  is  not  to  be  used  for  drinking  pur- 
poses. 

One  of  the  most  carefully  conducted  establishments 
for  the  disposal  of  sewage  by  chemical  precipitation  is 
that  at  Worcester,  Mass.,  and  the  chemical  examinations 
of  the  effluent,  there  constantly  made,  show  an  average 
reduction  of  95  per  cent  of  the  suspended  and  about  53  per 
cent  of  the  dissolved  organic  matters  of  the  sewage.  It  is 
fair  to  state,  however,  that  Worcester  has  been  called  upon 
to  defend  the  process  before  the  law  on  complaint  of  Mill- 
bury,  a  town  below  Worcester,  on  the  Blackstone  river  into 
which  the  effluent  from  the  Worcester  purification  plant  is 
poured.  Millbury  has  claimed  that  the  purification  of  the 
effluent  is  inadequate,  and  that  a  nuisance  which  exists 
there  is  due  to  imperfect  purification  of  the  sewage  of 
Worcester.  On  trial  it  appeared  that  there  was  among  the 
most  competent  experts  a  great  difference  of  opinion  as  to 
the  sanitary  efficiency  of  the  process. 

The  reader  who  cares  to  pursue  the  subject  of  chemical 
precipitation  further  is  referred  to  the  following :  Hazen, 
"  Experiments  on  the  Chemical  Precipitation  Sewage," 
Massachusetts  Special  Report,  State  Board  of  Health,  1890, 
p.  734.  Ibid.,  "  Chemical  Precipitation  of  Sewage  at  the 
World's  Fair,  Chicago,  1893."  Massachusetts  Report,  1892, 
p.  595.  "  Annual  Reports  "  of  H.  P.  Eddy,  Superintend- 
ent of  Sewers,  City  of  Worcester,  Mass.  Baker  and  Raf- 
ter, "  Sewage  Disposal  in  the  United  States."  (D.  Van 
Nostrand  Co.),  New  York. 

§  24. —  Sewage  Disposal  and  Purification  by  Electricity 

The  extensive  development  of  electrical  appliances  has 
naturally  led  to  various  proposals  for  the  purification  of 
sewage  by  electrical  means.  It  can  hardly  be  said,  how- 


ELECTRICAL  PURIFICATION   OF   SEWAGE          157 

ever,  as  yet,  that  any  of  these  has  attained  a  practical 
importance  such  as  would  entitle  it  to  consideration. 

The  principles  involved  in  the  electrical  purification  of 
sewage  have  been  clearly  stated,  and  the  recent  state  of 
the  subject  ably' summarized,  by  Professor  (now  President) 
Thomas  M.  Drown,1  of  Lehigh  University,  chemist  to  the 
State  Board  of  Health  of  Massachusetts,  in  the  following 
words :  — 

"  We  may  distinguish  two  classes  of  so-called  electrical  purification : 
first,  those  which  electrolyze  water,  liberating  oxygen  at  the  positive 
pole ;  and,  second,  those  which  electrolyze  a  solution  of  common  salt 
and  liberate  chlorine  in  the  same  way. 

"  The  Webster  process  for  the  purification  of  sewage,  of  which  a 
good  deal  was  once  heard,  belonged  mainly  to  the  first  class,  although 
by  reason  of  the  chlorides  contained  in  the  sewage  it  fell  also,  in  part, 
into  the  second  class.  The  oxygen  liberated  at  the  positive  pole,  while 
in  the  nascent  state,  was  supposed  to  oxidize  some  organic  matter;  but 
as  the  pole  was  composed  of  iron  plates,  the  oxygen  was  mainly  con- 
sumed in  oxidizing  this  iron,  and  the  oxide  of  iron  thus  formed  acted 
as  a  precipitating  agent  on  the  sludge  in  the  sewage.  The  process  was 
thus  mainly  one  of  chemical  precipitation  of  sewage  by  means  of  oxide 
of  iron,  which  was  formed  by  a  current  of  electricity  passing  through 
the  sewage.  .  .  . 

"  The  possibility  of  oxidizing  organic  matter  on  the  large  scale  by 
means  of  nascent  oxygen  liberated  from  water  by  the  electric  current 
will,  probably,  never  be  more  than  a  dream.  Attractive  as  the  process 
seems,  the  necessary  conditions  for  accomplishing  it  could  probably 
never  be  realized  on  a  city's  water  supply,  or  on  its  sewage.  .  .  . 

"  The  more  recent  systems  of  purification  of  water  and  sewage  by 
electricity  belong  in  the  second  class,  that  is,  the  decomposition  by 
electrolysis  of  a  solution  of  common  salt.  .  .  . 

"  The  principal  product,  under  ordinary  conditions,  is  sodium  hypo- 
chlorite.  .  .  . 

"  This,  then,  sodium  hypochlorite,  is  the  substance  with  which  we 
have  to  deal  in  the  method  of  electrical  purification  which  depends  on 
the  electrolysis  of  a  solution  of  salt  or  sea  water.  When  the  current  of 
electricity  has,  in  the  manner  above  described,  formed  a  sufficiently 
concentrated  solution  of  sodium  hypochlorite,  this  solution  is  mixed 
with  the  water  or  sewage  to  be  purified.  .  .  . 

^•Journal  Neiv  England  Water  Works  Association,  VIII  (1894),  pp.  183- 
188.  "On  the  Electrical  Purification  of  Water  [and  Sewage]." 


158  ON   SEWAGE  AND  ITS  PURIFICATION 

"  The  so-called  '  electrical '  purification  of  water  by  treating  it  with 
an  electrolyzed  solution  of  salt  is  thus  seen  to  be  simply  a  process  of 
disinfection  by  sodium  hypochlorite ;  electricity,  as  such,  has  nothing 
to  do  with  it.  ... 

"  Ozone  is  generally  supposed  to  cover  a  multitude  of  sins  of  pollu- 
tion, and  quickly  to  destroy  them ;  but  we  do  not  know  much,  if  any- 
thing, about  its  germicidal  power ;  and  there  is  certainly  no  good  reason 
for  attributing  any  of  the  disinfecting  action  of  an  electrolyzed  salt  solu- 
tion to  ozone,  even  did  we  certainly  know  it  to  be  present. 

"  It  is  unfortunate  that  the  advocates  of  this  system  of  purification  of 
water  and  sewage  are  not  content  to  attribute  the  purifying  action  of  the 
electrolyzed  solution  of  salt  solely  to  the  hypochlorite  formed.  There 
is  nothing  gained  by  calling  it  '  electrozone,'  or  an  '  electro-saline  solu- 
tion,' for  there  is  nothing  mysterious  about  its  action,  as  these  terms 
would  lead  one  to  suppose.  Nor  is  it  proper  to  speak  of  this  system  of 
purification  as  in  any  sense  an  'electrical'  one.  If  one  were  to  pur- 
chase two  bottles  of  sodium  hypochlorite  of  identically  the  same  com- 
position, one  prepared  by  a  chemical  process  and  the  other  by  the 
electrolysis  of  a  salt  solution,  he  would  not  expect  to  find  them  called 
by  different  names.  To  call  the  latter  an  'electrical  disinfectant' 
would  be  simply  fantastic." 

§  25.  —  Sewage  Disposal  and  tlie  Partial  Self-Purification 
of  Sewage  by  Means  of  Fermentation  or  Putrefaction. 

A  recent  and  interesting  development  in  the  theory  and 
practice  of  sewage  disposal  and  purification  is  that  known 
as  the  septic  process,  in  which  advantage  is  taken  of  the 
fact  that  sewage  is  a  highly  putrescible  fluid  richly  charged 
with  putrefactive  bacteria,  in  order  to  decompose  it  by  its 
own  ordinary  processes  of  bacterial  fermentation  or  putre- 
faction, thus  bringing  it  into  a  condition  in  which  it  is 
believed  to  be  more  readily  nitrified  when,  subsequently,  it 
is  brought  in  contact  with  the  living  earth,  and,  in  particu- 
lar, causing  suspended  matters  (sludge)  to  pass  partly  or 
wholly  into  solution. 

The  process  consists  simply  in  allowing  ordinary  town 
sewage  to  stagnate,  ferment  and  putrefy  in  a  tank  or 
tanks  for  a  somewhat  longer  time  than  usual.  Under 
these  circumstances,  the  sewage  contains  no  free  oxygen,/ 


SELF-PURIFICATION   BY   PUTREFACTION  159 

and  Pasteur's  original  idea  of  fermentation  as  "  life  without 
air"  is  fully  realized.  According  to  the  evidence  of  vari- 
ous observers,  the  organic  matter  is  thus  more  thoroughly 
decomposed,  and  the  sewage  is  more  quickly  brought  into 
a  condition  in  which  it  is  readily  nitrified  when,  as  is  the 
practice,'  it  is  afterward  run  through  slow  sand  filters  in 
the  usual  methods  of  intermittent  filtration,  or  by  the  in- 
genious modification  of  intermittent  filtration  known  as 
"contact  filters,"  proposed  by  Dibdin.  Further  details  and 
a  full  account  of  the  various  processes  employed  may  be 
found  in  a  valuable  paper  by  Professor  L.  P.  Kinnicutt, 
entitled  "Purification  of  Sewage  by  Bacterial  Methods," 
Journal  New  England  Water  Works  Association,  Vol.  XV, 
p.  119.  Boston,  1900.  See  also  the  "Annual  Reports"  of 
the  Connecticut  State  Sewerage  Commission,  begun  in  1899. 

§  26.  —  Fate  of  the  Infectious  Matters  in  Sewage  Disposal 
and  Sewage  Purification 

For  the  student  of  sanitary  science,  and  from  the  prac- 
tical point  of  view,  it  is  a  question  of  the  highest  importance 
what  becomes  of  the  infectious  materials  in  sewage  when 
the  latter  is  disposed  of,  or  purified,  by  any  of  the  various 
methods  described  above. 

In  the  case  of  disposal  by  dilution,  there  is  reason  to 
believe  that  much  depends  on  the  special  conditions  under 
which  the  dilution  takes  place.  If,  for  example,  a  moder- 
ate amount  of  sewage  is  emptied  into  a  relatively  large 
body  of  quiet  water,  we  may  safely  suppose  that  the  infec- 
tious materials  which  it  contains,  namely,  micro-organisms 
of  various  kinds,  are  for  the  most  part  unfavorably  affected 
by  the  new  environment  with  which  they  are  likely  to  meet, 
and,  under  the  influence  of  light,  gravity,  defective  food 
supply  and  possibly  predatory  infusoria  or  other  enemies, 
as  well  as  unfavorable  temperatures,  gradually  perish  at 
a  point  not  very  distant  from  that  at  which  they  were  dis- 


160  ON   SEWAGE  AND   ITS   PURIFICATION 

charged.  Indeed,  it  is  impossible  on  any  other  hypothesis 
to  explain  the  facts  which  have  been  observed  in  cases  like 
those  of  Burlington,  Cleveland,  Chicago,  Milwaukee,  etc. 

It  is  quite  otherwise,  however,  with  those  cases  of  puri- 
fication by  dilution,  in  which  the  sewage  forms  a  relatively 
large  part  of  the  body  of  the  water  into  which  it  is  emptied, 
and  especially  in  those  cases  in  which  it  is  carried  swiftly 
by  running  streams  or  currents  within  a  short  time  to  points 
comparatively  remote  from  the  place  of  disposal.  In  these 
cases,  the  same  forces  —  light,  gravity,  temperature  and, 
in  general,  unfavorable  environment  —  would  be  operative, 
but  yet  the  practical  outcome  might  be  that  these  were 
less  availing,  while  the  want  of  one  other  important  ele- 
ment, time,  would  be  favorable  to  the  persistence  of  vitality 
of  the  micro-organisms  which  might  therefore  arrive,  in  a 
state  of  dilution  to  be  sure,  but  yet,  at  comparatively  remote 
points,  quickly  and  therefore  alive  and  virulent.  It  is  for 
this  reason  that  we  are  forced  to  conclude,  contrary  to  the 
opinions  held  only  a  few  years  since,  that  quiet  water,  and 
not  running  water,  purifies  itself.  But  to  this  subject  we 
shall  return  (in  Chapter  IX). 

When  we  come  to  the  disposal  of  sewage  upon  land,  we 
find  the  question  of  the  fate  of  infectious  materials  in  the 
sewage  entirely  different.  If,  as  is  always  assumed,  the  sew- 
age to  be  purified  is  passed  through,  and  not  merely  over,  the 
earth,  the  micro-organisms  which  it  contains  are  held  back 
more  or  less  completely,  along  with  other  suspended  matters, 
by  the  living  earth.  One  of  the  most  striking  phenomena  of 
intermittent  filtration  which,  as  we  have  shown,  is  the 
fundamental  process  in  all  land  treatment  of  sewage,  is  the 
disappearance  of  the  very  numerous  living  bacteria  always 
present  in  the  crude  sewage.  Some  of  these,  no  doubt,  are 
mechanically  detained  in  the  upper  layers  of  the  living 
earth,  the  jelly-like  masses  which  exist  there  being  espe- 
cially favorable  for  entanglement  of  their  cilia.  Others 
perish  from  lack  of  food,  either  near  the  surface  or,  more 


FATE   OF   ITS   INFECTIOUS   MATERIALS  161 

probably,  in  the  lower  layers  of  the  filter,  or  still  further 
down,  in  the  now  purified  effluent  which  has  been  robbed 
of  the  food  materials  but  lately  abundant  in  it.  In  the 
sewage  filters  at  the  Lawrence  Experiment  Station  it  very 
early  became  evident  that  a  high  degree  of  nitrification  was 
accompanied  by  a  remarkable  disappearance  of  bacteria, 
and  repeated  experiments  have  shown  that  the  effluent 
from  a  good  sewage  filter  is  incapable  of  supporting  any 
considerable  population  of  bacteria.  There  is  no  doubt 
that  under  certain  circumstances  bacteria  applied  to  the  sur- 
face of  an  intermittent  filter  may  live  to  find  their  way  into 
the  effluent,  as  was  proved  for  the  first  time  at  the  Law- 
rence Experiment  Station  by  experiments  made  in  1888 
and  published  in  1 8go.1  The  same  thing  was  shown  a  little 
later  by  the  experiments  of  Fraenkel  and  Pief  ke,2  and  the 
fact  is  now  generally  accepted. 

On  the  other  hand,  it  is  the  universal  testimony  of  those 
familiar  with  intermittent  filters  and  sewage  farms  that  the 
ordinary  effluent  waters  derived  from  well-regulated  filters 
may  be,  and  often  are,  drunk  with  impunity.  We  do  not 
know  how  small  a  number  of  pathogenic  bacteria  may  under 
certain  circumstances  produce  disease.  But  there  is  good 
reason  to  think  that  the  danger  of  infection  in  any  particu- 
lar case  depends,  in  part  at  least,  upon  the  size  of  the  dose, 
which  would  mean  the  number  of  micro-organisms  intro- 
duced into  the  body.  It  is  not  claimed  that  sewage  efflu- 
ents are  desirable  for  drinking  waters ;  but  there  is  very 
little  doubt  that  the  effluents  from  well-regulated  filters  or 
sewage  farms  may  be  safely  introduced  into  streams  or 
other  bodies  of  water,  even  those  which  are  later  to  be 
used  as  sources  of  water  supply. 

1 "  Experimental  Investigations  by  the  State  Board  of  Health  of  Massachu- 
setts on  the  Purification  of  Sewage  and  Water,"  1888-1890,  p.  852.  Boston, 
1890. 

2  Zeit.  fiir  Hygiene,  8,  1890.     See  also  Bertschinger,  Vierteljahreschrift  d. 
Naturforsch.  Geselhch*  in  Zurich,  1889. 
M 


1 62  ON   SEWAGE  AND   ITS  PURIFICATION 

If  it  be  asked,  what  becomes  of  the  infectious  materials 
held  back  by  the  soil  ?  the  answer  is  that  they  do  not  appear 
ordinarily  to  multiply,  but  rather  to  perish,  along  with  the 
myriads  of  putrefactive  bacteria  which  accompany  them  in 
the  sewage.  No  fact  is  more  striking  in  the  history  of  the 
experimental  filters  at  Lawrence  than  that  these  are  vast 
charnel  houses  for  bacteria.  The  sewage  applied  to  the  fil- 
ters contains,  on  the  average,  one  or  two  millions  of  bacteria 
per  cubic  centimetre.  The  effluent  drawn  off  at  the  bottom 
contains  at  most  only  hundreds  or  thousands,  and  this  state 
of  affairs  is  continuous  day  after  day,  month  after  month 
and  year  after  year.  And  yet,  at  the  same  time,  there 
appears  to  be  a  living  resident  population,  tolerably  con- 
stant in  numbers,  distributed  through  the  different  layers 
of  the  filter.  In  view  of  this  and  similar  facts,  we  have 
above  referred  to  the  earth  as  the  home  of  the  bacteria ; 
but  in  view  also  of  the  enormous  mortality  of  the  bacteria 
in  a  sewage  filter,  it  is  equally  clear  that  the  earth  may  be 
no  less  truly  their  tomb ;  and  it  appears  to  be  here  that  the 
infectious  micro-organisms  present  in  the  sewage  find, 
fortunately,  in  this  particular  form  of  sewage  disposal, 
their  last  resting-place. 

In  the  case  of  purification  of  sewage  by  chemical  pre- 
cipitation, we  may  reasonably  suppose  that  most  of  the 
infectious  materials  are  carried  down  by  the  precipitant 
and  got  rid  of  in  the  sludge.  In  any  event,  however,  the 
fate  of  the  infectious  materials  in  this  case  is  of  less  im- 
portance, inasmuch  as  effluents  from  chemical  precipitation 
works  are  not,  as  a  rule,  and  cannot  safely  be,  at  least 
in  America,  admitted  into  a  body  of  water  used  for  drink- 
ing purposes. 

It  has, been  urged  in  favor  of  the  electrical  purification 
of  sewage  that  the  infectious  materials  present  are  readily 
destroyed  by  the  electric  currents  employed.  But  this,  in 
view  of  various  experiments  touching  the  effect  of  electricity 
upon  bacteria  and  other  micro-organisms  is,  to  say  the 


SEWAGE   FILTERS   AS   BACTERIAL  TOMBS         163 

least,  doubtful ;  and  if  what  has  been  stated  above  in  regard 
to  the  real  nature  of  this  method  of  purification  is  true,  the 
problem  here  does  not  differ  essentially  from  that  affecting 
chemical  precipitation,  which  has  just  been  considered. 

As  to  the  effect  produced  by  the  natural,  fermentation  or 
septic,  process,  especially  when  combined  with  Dibdin's  con- 
tact filters,  such  as  are  in  use  at  Exeter  and  Manchester,  in 
England,  very  little  is  as  yet  known ;  but  it  is  fair  to  sup- 
pose that  the  fermenting  process  in  the  tank,  in  the  absence 
of  oxygen,  as  well  as  the  nitrifying  process  in  the  filters  in 
the  presence  of  oxygen,  are  highly  unfavorable  to  the  con- 
tinued life,  and  still  less  to  the  multiplication,  of  infectious 
materials.  We  may  safely  predict  that  these  processes 
will  prove  to  be  entirely  satisfactory  so  far  as  the  puri- 
fication of  the  sewage  in  respect  to  infectious  matters  is 
concerned. 


CHAPTER  VIII 

ON  WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE.  THE 
POLLUTION  OF  PUBLIC  WATER  SUPPLIES.  NOTABLE  EPI- 
DEMICS DUE  TO  INFECTED  DRINKING  WATER 

"  My  reports  are  incessantly  showing  the  foulness  of  private  supplies 
while  as  regards  public  water  supplies  ...  it  has  again  and  again  been 
shown  that  their  conveniences  and  advantages  are  countervailed  by 
dangers  to  life  on  a  scale  of  gigantic  magnitude."  —  SIR  JOHN  SIMON, 
Ninth  Report,  Medical  Officer  of  the  Privy  Council,  p.  34.  London, 
1867. 

"  The  events  I  am  going  to  relate  to  you  would,  in  the  Middle  Ages, 
have  been  ascribed  to  some  mysterious  influence  or  to  supernatural  per- 
secution. Science  now  enlightens  us  on  the  true  cause  of  the  evil,  but 
at  the  same  time  imposes  upon  us  the  obligation  to  employ  all  the 
resources  it  gives  us  to  combat  the  danger,  which  belongs  to  a  class  that 
human  prudence  can  avoid."  —  DR.  GUENEAU  DE  MUSSY,  on  lead  poison- 
ing in  the  family  of  Louis  Philippe  from  the  water  supply  of  the  royal 
palace  of  Claremont. 

INASMUCH  as  sewage  may  contain  any  or  all  of  the  infec- 
tious materials  from  diseased  animal  bodies,  and  inasmuch, 
further,  as  it  is  a  liquid  readily  miscible  with  water,  —  being 
itself  hardly  more  than  very  dirty  water,  —  while  it  is  also 
produced  in  relatively  large  quantities  by  modern  commu- 
nities, it  is  perhaps  not  to  be  wondered  at  that  the  germs 
of  disease  often  find  access  to  wells,  springs,  reservoirs 
and  streams,  from  which  water  is  destined  sooner  or  later 
to  be  drawn  for  drinking  purposes. 

§  I. — Drinking  Water  as  a  Vehicle  of  Disease 

It  has  been  shown  above  (Chapter  V)  that  while  infec- 
tious materials  may  sometimes  enter  the  body  through  the 

164 


PURE    VS.   POLLUTED  WATERS  165 

skin,  the  more  common  and  the  easier  avenues  are  those  of 
the  alimentary,  pulmonary  and  genito-urinary  tracts.  Of 
all  the  substances  admitted  into  the  alimentary  canal,  the 
most  abundant,  and  perhaps  the  most  trusted,  is  water. 
The  "  cup  of  cold  water  "  has  long  stood  as  the  symbol  of 
charity ;  and  yet,  from  the  sanitary  point  of  view,  there  is 
little  or  no  doubt  that  water  is  one  of  the  most  dangerous 
vehicles  of  disease  which  passes  through  the  gates  leading 
into  the  human  body. 

Water  chemically  pure  should,  of  course,  contain  no 
infectious  materials,  although  it  is  an  interesting  fact  that 
in  laboratory  experiments  it  is  possible  to  introduce  into 
distilled  water  a  considerable  number  of  pathogenic  bac- 
teria without  producing  any  effect  upon  the  water  discover- 
able by  the  most  refined  chemical  analysis.  Again,  it  is 
quite  possible,  in  laboratory  experiments,  to  mingle  with 
a  specimen  of  water  millions  of  the  germs  of  typhoid  fever 
or  Asiatic  cholera  without  effecting  perceptibly  its  bright 
and  attractive  appearance.  With  these  facts  in  mind  it 
becomes  comparatively  easy  to  understand  that  water  may 
appear  bright  and  attractive  to  the  eye  and  be  acceptable 
to  the  palate,  while  yet  containing  myriads  of  disease 
germs.  It  should  not  be  forgotten,  however,  that  what 
has  been  stated  is  true  only  of  laboratory  experiments, 
and  rarely,  if  ever,  happens  or  is  likely  to  happen  under 
natural  conditions  or  on  a  large  scale. 

Natural  waters,  such  as  those  of  springs  and  wells,  brooks 
and  other  streams  from  uninhabited  districts,  should  con- 
tain, and  ordinarily  do  contain,  no  infectious  materials  ;  and 
such  waters,  although  they  may  contain  mud,  or  various 
vegetable  and  even  animal  matters,  are  commonly  described 
as  "pure."  But  it  is  very  different  with  natural  waters 
which  have  been  exposed  to  pollution,  especially  by  sewage. 
From  what  has  already  been  said  it  is  clear  that  the  latter 
may  and  frequently  does  contain  infectious  materials ;  so 
that  if  sewage  in  any  form  finds  its  way  into  drinking 


166    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

waters,  these  are  more  than  likely  to  prove  a  convenient 
vehicle  for  the  conveyance  of  infectious  materials  into  the 
human  body.  Even  if  sewage  has  been  somewhat  purified 
by  dilution  or  other  treatment,  its  presence  in  waters  used 
for  drinking  properly  constitutes  a  source  of  anxiety,  the 
precise  danger  involved  depending  in  any  special  case  upon 
the  degree  of  purification  which  they  have  undergone ; 
and  it  is  obvious  that  the  determination  of  the  degree  of 
purification  in  any  particular  case  of  pollution  may  be  a 
special  problem  taxing  the  best  resources  of  the  sanitarian. 

§  2. — Diarrhceal  Diseases  and  Drinking  Water 

A  little  reflection  will  show  that  while  diseases  of  the 
skin,  the  throat,  the  lungs,  the  nose,  etc.,  are  accompanied 
by  eruptions,  exudations,  expectorations  or  other  discharges 
which  may  find  their  way  into  sewage,  these  are  usually 
insignificant  in  amount  in  comparison  with  the  bowel  dis- 
charges. It  is  not  surprising,  therefore,  to  learn  that 
diseases  affecting  the  alimentary  canal,  and  especially  the 
intestine,  particularly  if  accompanied  by  diarrhoea,  are 
most  conspicuous  among  the  diseases  conveyed  by  sew- 
age-polluted drinking  water.  It  is  now  well  established 
that  certain  bowel  diseases,  such  as  typhoid  fever  and 
Asiatic  cholera,  are  readily  conveyed  by[drinking  water,  and 
numerous  epidemics  of  these  diseases  have  been  traced  to 
infected  water  supplies;  but  there  is  very  little  evidence  of 
the  conveyance  of  diseases  of  the  skin,  throat,  lungs  and 
nose  by  this  particular  vehicle.  Moreover,  there  are  certain 
members  even  of  the  group  of  diseases  known  as  "  diar- 
rhceal"  which  do  not  seem  to  be  as  readily  conveyed  by  drink- 
ing water  as  are  others  of  the  same  class.  Cholera  inf  antum, 
for  example,  is  a  common,  severe  and  often  fatal  diarrhoeal 
disease  of  children.  But  it  seems  seldom,  if  ever,  traceable 
to  polluted  drinking  water,  with  which  typhoid  fever  and 
Asiatic  cholera  can  very  often  be  directly  connected. 


SOME   DISEASES   NOT  WATER-BORNE  167 

§  3. —  Typhoid  Fever  and  Asiatic  Cholera 

These  two  diseases,  and  especially  typhoid  fever,  are  of 
preeminent  importance  and  interest  to  the  student  of  sani- 
tary science,  and  for  this  reason  a  short  account  of  their 
natural  history  will  be  given  at  this  point  as  a  preface  to 
further  consideration  of  them.  As  long  ago  as  1874  expert 
opinion  had  concluded  that  "  the  existence  of  specific 
poisons  capable  of  producing  cholera  and  typhoid  fever  is 
attested  by  evidence  so  abundant  and  strong  as  to  be  prac- 
tically irresistible.  These  poisons  are  contained  in  the 
discharges  from  the  bowels  of  persons  suffering  from  these 
diseases." — Rivers  Pollution  Commission  of  1868,  Sixth 
Report,  p.  427.  London,  1874. 

Typhoid  fever  is  so  called  because  it  resembles,  and  was 
not  formerly  distinguishable  from,  typhus  fever,  otherwise 
known  as  "ship,"  "jail"  or  "spotted"  fever.  It  is  char- 
acterized by  slow  and  insidious  onset  during  a  period  lasting 
for  about  two  weeks,  and  known  as  the  "  prodeomal "  period, 
during  which  the  patient  generally  suffers  from  severe 
frontal  headache,  often  having  in  addition  backache,  nose- 
bleed, diarrhoea  and  a  general  loss  of  strength  which  finally, 
in  severe  cases,  compels  him  to  take  to  his  bed.  By  this 
time  active  fever  is  well  established,  the  temperature  rang- 
ing from  1 00°  to  105°  or  even  higher,  and  characterized  by 
a  daily  rise  in  the  evening  and  a  fall  in  the  morning. 
During  the  period  of  active  sickness,  which  usually  lasts 
from  four  to  eight  weeks,  delirium  sometimes  occurs,  and 
other  serious  symptoms  make  their  appearance.  It  is  a 
characteristic  of  the  disease,  and  one  which  distinguishes  it 
from  typhus  fever,  that  in  typhoid  fever  the  small  intestine 
undergoes  more  or  less  extensive  and  dangerous  ulcerations ; 
and  inasmuch  as  these  ulcers  burrow  into  the  wall  of  the 
intestinal  tube,  they  may  either  perforate  it,  allowing  faecal 
matters  to  enter  the  peritoneal  cavity,  and  causing  speedy 
death  from  septicaemia,  or  they  may  involve  important  blood 


.- 


168     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

vessels,  which  becoming  disintegrated  cause  profuse 
hemorrhages,  often  likewise  followed  by  speedy  death. 

Owing  to  the  fact  that  the  lower  animals  are  not,  so  far 
as  known,  susceptible  to  typhoid  fever,  it  has  never  been 
possible,  as  yet,  to  establish  with  absolute  certainty  the  iden- 
tity of  the  specific  germ  of  typhoid  fever.  At  the  same 
time  there  is  a  very  general  agreement  that  the  so-called 
Koch-Eberth-Gaffky  bacillus  is,  in  all  probability,  the  real 
and  specific  cause  of  the  disease.  The  commonly  accepted 
theory  of  the  causation  of  typhoid  fever  is,  that  the  specific 
bacilli,  making  their  way  into  the  alimentary  canal  in  such 
vehicles  as  water,  milk,  dirt  or  dust,  survive  the  journey 
through  the  stomach,  and  finding  themselves  in  the  intes- 
tine, there  multiply  and  produce  their  own  specific  toxin, 
to  the  absorption  of  which  are  due  the  earlier  symptoms 
of  the  disease.  Simultaneously,  or  possibly  subsequently, 
and  presumably  under  the  action  of  the  same  toxin,  the 
guardian  membranes  of  the  alimentary  tract  are  weakened 
or  otherwise  damaged,  so  that  their  usual  resistance  is 
somewhat  enfeebled,  and  the  bacilli  make  their  way  through 
them  into  the  tissues  of  the  body  proper.  Of  all  the  tis- 
sues the  spleen  seems  to  be  particularly  affected ;  and  it 
is  from  this  organ  that  those  bacilli  are  most  easily  recov- 
ered which  are  believed  to  be  specific  and  characteristic  of 
the  disease. 

If  these  commonly  accepted  ideas  are  correct,  it  is 
obvious  that  the  bowel  discharges  of  typhoid  fever 
patients  must  naturally  contain  large  numbers  of  the 
germs  of  typhoid  fever;  and  that  if  these  discharges  find 
their  way  into  sewage,  such  sewage  must  be  not  only  pol- 
luted with  the  ordinary  bowel  discharges,  but  also  actually 
infected  with  the  specific  germs  of  the  disease.  Further- 
more, if  this  sewage  happens  to  find  its  way  into  a  water 
supply  that  supply  is  liable  to  become  a  vehicle  of  disease 
unless  it  shall  somehow  have  been  purified  before  it  is  used 
for  drinking  purposes.  It  should  also  be  observed  in  pass- 


TYPHOID   FEVER   AND   ASIATIC   CHOLERA         169 

ing  that  the  journey  from  one  human  intestine  to  another 
may,  conceivably  at  least,  be  very  short,  very  direct  and 
very  quick;  and  it  is  also  easy  to  understand  that  the 
virulence  of  the  germs  may  well  depend  upon  various 
conditions  to  which  they  have  been  submitted  en  route. 

Asiatic  cholera  is  a  disease  in  many  respects  similar  to 
typhoid  fever,  but  more  violent,  more  rapid  and  more 
fatal.  In  this  case,  also,  owing  to  the  insusceptibility  of 
the  lower  animals  to  the  disease,  it  has  been  thus  far 
impossible  to  prove  absolutely  that  the  Spirillum,  or 
Vibrio,  generally  regarded  as  the  cause  of  the  disease, 
is  surely  such.  Certain  experiments,  voluntarily  made 
by  human  beings,  and  a  large  amount  of  circumstantial 
evidence,  have  made  it,  however,  highly  probable  that  the 
general  belief  that  we  know  the  real  germ  of  this  dis- 
ease is  correct.  (Cf.  p.  98.) 

In  this  case,  also,  it  is  held  that  the  germs  having  been 
taken  into  the  alimentary  canal  with  food  or  drink  or,  pos- 
sibly, air,  survive  the  journey  through  the  stomach,  and, 
arriving  in  the  intestine,  there  multiply  enormously,  pro- 
ducing at  the  same  time  their  specific  toxin,  which,  in 
cholera,  is  far  more  active  and  far  more  poisonous  than 
that  of  typhoid  fever.  The  toxin,  being  absorbed  into  the 
body  proper,  is  supposed  to  cause  those  profound  disturb- 
ances of  the  organism,  and  often  even  its  rapid  destruc- 
tion, which  are  so  characteristic  of  the  disease. 

In  the  case  of  typhoid  fever  it  was  until  recently  very 
difficult  to  demonstrate  with  certainty  the  presence  of 
typhoid  fever  bacilli  in  the  bowel  discharges  of  patients 
suffering  from  that  disease,  so  that  we  were  actually  in 
the  humiliating  position  of  attributing  to  these  discharges 
the  principal  agency  in  the  distribution  of  typhoid  fever, 
while  yet  we  were  quite  unable  satisfactorily  to  prove 
the  presence  of  the  germs  in  the  discharges.  From  this 
unfortunate  dilemma  we  seem  to  have  been  relieved  by 
the  Widal  serum  test,  so  that  at  present  it  is  held  to  be 


I/O    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

easy  to  make  the  demonstration  so  desirable.  In  the  case 
of  Asiatic  cholera,  on  the  other  hand,  the  number  of 
micro-organisms  present  in  the  bowel  discharges  is  so  enor- 
mous that  it  has  been  from  the  start  easy  to  dem- 
onstrate their  existence;  and  there  is  no  difficulty  in 
understanding  how  it  is  that  the  bowel  discharges  of  a 
single  patient  suffering  from  this  disease  may  not  only 
pollute,  but  also  specifically  infect,  a  particular  specimen 
of  sewage,  with  which,  in  turn,  infection  may  pass  into 
a  water  supply  and,  under  certain  conditions,  arrive  in  the 
alimentary  canal  of  a  person  drinking  the  infected  water. 
Here,  also,  it  is  easy  to  follow  the  infection  from  one  intes- 
tine to  another,  and,  as  in  the  case  of  typhoid  fever,  the 
extent  and  virulence  of  the  infection  will  obviously  depend 
upon  a  number  of  conditions  en  route,  such  as  time, 
temperature,  food  supply,  gravity,  light  and  mechanical 
obstructions. 

§  4. — An  Epidemic  of  Asiatic  Cholera  traced  to  a    Well. 
The  Case  of  the  Broad  Street  (Londoti)  Pump 

One  of  the  earliest,  one  of  the  most  famous,  and  one 
of  the  most  instructive  cases  of  the  conveyance  of  disease 
by  polluted  water  is  that  commonly  known  as  the  epidemic 
of  Asiatic  cholera  connected  with  a  Broad  Street  (Lon- 
don) well,  which  occurred  in  1854.  For  its  conspicuously 
circumscribed  character,  its  violence  and  fatality,  and  espe- 
cially for  the  remarkable  skill,  thoroughness  and  success 
with  which  it  was  investigated,  it  will  long  remain  one  of 
the  classical  instances  of  the  terrible  efficiency  of  polluted 
water  as  a  vehicle  of  disease.  As  a  monument  of  sanitary 
research,  of  medical  and  engineering  interest  and  of  pene- 
trating inductive  reasoning,  it  deserves  the  most  careful 
study.  No  apology,  therefore,  need  be  made  for  giving 
of  it  here  a  somewhat  extended  account.1 

1  The  complete  original  report  is  entitled  "  Report  on  the  Cholera  Out- 
break in  the  Parish  of  St.  James,  Westminster,  during  the  Autumn  of  1854. 


DRINKING   WATER  AND  ASIATIC   CHOLERA       171 


(a)  —  The  Parish  of  St.  James,    Westminster,  in 

The  parish  of  St.  James,  Westminster  (London),  occu- 
pied in  1854,  164  acres,  and  contained  in  1851,  36,406 
inhabitants.  It  was  divided  into  three  subdistricts,  viz., 
those  of  St.  James's  Square,  Golden  Square,  and  Berwick 
Street.  As  will  be  seen  by  the  map  (at  p.  174),  it  was 
situated  near  a  part  of  London  now  well  known  to  travel- 
lers, not  far  from  the  junction  of  Regent  and  Oxford 
streets.  It  was  bounded  by  May  Fair  and  Hanover  Square 
on  the  west,  by  All  Souls  and  Marylebone  on  the  north, 
St.  Anne's  and  Soho  on  the  east  and  Charing  Cross  and 
St.  Martin's-in-the-Fields  on  the  east  and  south. 

In  the  cholera  epidemics  of  1832,  1848-1849,  and  1853, 
St.  James's  Parish  suffered  somewhat  but,  on  the  aver- 
age, decidedly  less  than  London  as  a  whole.  In  1854,  how- 
ever, the  reverse  was  the  case.  The  Inquiry  Committee 
estimated  that  in  this  year  "  the  fatal  attacks  in  St.  James's 
Parish  were  probably  not  less  than  700,"  and  from  this 
estimate  computed  a  cholera  death-rate,  during  17  weeks 
under  consideration,  of  220  per  10,000  living  in  the  parish, 
which  was  far  above  the  highest  in  any  other  district.  In 
the  adjoining  subdistrict  of  Hanover  Square  the  ratio  was 
9  ;  and  in  the  Charing  Cross  district  of  St.  Martin's-in-the- 
Fields  (including  a  hospital)  it  was  33.  In  1848-1849  the 
cholera  mortality  in  St.  James's  Parish  had  been  only  15 
per  10,000  inhabitants. 

(b)  —  The  Search  for  the  Source  of  the  Epidemic 

Within  the  parish  itself  the  disease  in  1854  was  very 
unequally  distributed.  In  the  St.  James's  Square  district 
the  cholera  mortality  was  only  16  per  10,000,  while  in  the 
Golden  Square  district  it  was  217,  and  in  the  Berwick 

Presented  to   the   Vestry  by  the  Cholera  Inquiry  Committee,  July,  1855." 
London,  J.  Churchill,  1855. 


1/2     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

Street  district,  212.  It  was  plain  that  there  had  been  a 
special  cholera  area,  a  localized,  circumscribed  district. 
This  was  eventually  minutely  studied  in  the  most  pains- 
taking fashion  as  to  population,  industries,  previous  sani- 
tary history,  meteorological  conditions  and  other  general 
phenomena  common  to  London  as  a  whole;  with  the 
result  that  it  was  found  to  have  shared  with  the  rest  of 
London  "  a  previous  long-continued  absence  of  rain  .  .  . ; 
a  high  state  of  temperature  both  of  the  air  and  of  the 
Thames  .  .  . ;  an  unusual  stagnation  of  the  lower  strata 
of  the  atmosphere,  highly  favorable  to  its  acquisition  of 
impurity  .  .  . ;  and  although  it  was  impossible  ...  to  fix 
the  precise  share  which  each  of  the  conditions  enumerated 
might  separately  have  had  in  favoring  the  spread  of 
cholera,  the  whole  history  of  that  malady,  as  well  as  of 
the  epidemic  of  1854,  and  indeed  of  the  plagues  of  past 
epochs,  justifies  the  supposition  that  their  combined  opera- 
tion, either  by  favoring  a  general  impurity  in  the  air  or  in 
some  other  way,  concurred  in  a  decided  manner,  last  sum- 
mer and  autumn  (1854),  to  give  temporary  activity  to  the 
special  cause  of  that  disease."  (Report  of  Cholera  Inquiry 
Committee,  pp.  38,  39.)  The  Inquiry  Committee  did  not, 
however,  rest  satisfied  with  these  vague  speculations  and 
conclusions.  "...  But,  as  previously  shown  in  the  history 
of  this  local  outbreak,  the  resulting  mortality  was  so  dispro- 
portioned  to  that  in  the  rest  of  the  metropolis,  and  more 
particularly  to  that  in  the  immediately  surrounding  dis- 
tricts, that  we  must  seek  more  narrowly  and  locally  for 
some  peculiar  conditions  which  may  help  to  explain  this 
serious  visitation." 

Accordingly,  special  inquiries  were  made  within  the  dis- 
trict involved  in  regard  to  its  "  elevation  of  site  " ;  "  soil 
and  subsoil"  (including  an  extended  inquiry  into  the  his- 
tory of  a  "pest-field,"  said  to  have  been  located  within  this 
area  in  1665-1666,  to  which  some  had  attributed  the  cholera 
of  1854);  "surface  and  ground  plan";  "streets  and 


ASIATIC   CHOLERA  AND   THE   BROAD   ST.   PUMP     173 

courts";  "density  of  population";  "character  of  the 
population";  "dwelling  houses  —  internal  economy  as  to 
space,  light,  ventilation  and  general  cleanliness";  "dust- 
bins and  accumulations  in  yards,  cellars  and  areas " ; 
"  cesspools,  closets  and  house-drains  "  ;  "  sewers,  their 
waterflow  and  atmospheric  connection  "  ;  "  public  water 
supply  "  ;  and  "  well-water  supply."  No  peculiar  condi- 
tion or  adequate  explanation  of  the  origin  of  the  epidemic 
was  discovered  in  any  of  these,  even  after  the  most  search- 
ing inquiry,  except  in  the  well-water  supply.  Abundant 
general  defects  were  found  in  the  other  sanitary  factors, 
but  nothing  peculiar  to  the  cholera  area,  or,  if  peculiar, 
common  to  those  attacked  by  the  disease,  could  be  found 
excepting  the  supply  of  well  water. 

(c) — Suspicion  falls  upon  the  Broad  Street  Pump.     The 
Investigations  of  Dr.  John  Snow. 

At  the  very  beginning  of  the  outbreak,  Dr.  John  Snow, 
with  commendable  energy,  had  taken  the  trouble  to  get 
the  number  and  location  of  the  fatal  cases,  as  is  stated  in 
his  own  report  (Report  of  Cholera  Inquiry  Committee,  pp. 
100  et  seq.):  — 

"  I  requested  permission,  on  the  5th  of  September,  to 
take  a  list,  at  the  General  Register  Office,  of  the  deaths 
from  cholera  registered  during  the  week  ending  the  2d  of 
September  in  the  subdistricts  of  Golden  Square  and  Ber- 
wick Street,  St.  James's,  and  St.  Anne's,  Soho,  which  was 
kindly  granted.  Eighty-nine  (89)  deaths  from  cholera  were 
registered  during  the  week  in  the  three  subdistricts.  Of 
these  only  six  (6)  occurred  on  the  first  four  days  of  the 
week ;  four  (4)  occurred  on  Thursday,  August  3 1 ;  and 
the  remaining  79  on  Friday  and  Saturday.  I  considered, 
therefore,  that  the  outbreak  commenced  on  the  Thursday ; 
and  I  made  inquiry  in  detail  respecting  the  83  deaths 
registered  as  having  taken  place  during  the  last  three  days 
of  the  week. 


174     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

"  On  proceeding  to  the  spot  I  found  that  nearly  all  the 
deaths  had  taken  place  within  a  short  distance  of  the  pump 
in  Broad  Street.  There  were  only  ten  (ro)  deaths  in 
houses  situated  decidedly  nearer  to  another  street  pump. 
In  five  (5)  of  these  cases  the  families  of  the  deceased 
persons 'Told  me  that  they  always  sent  to  the  pump  in 
Broad  Street,  as  they  preferred  the  water  to  that  of  the 
pump  which  was  nearer.  In  three  other  cases,  the  de- 
ceased were  children  who  went  to  school  near  the  pump 
in  Broad  Street.  Two  of  them  were  known  to  have  drunk 
the  water,  and  the  parents  of  the  third  think  it  probable 
that  it  did  so.  The  other  two  deaths  beyond  the  district 
which  the  pump  supplies  represent  only  the  amount  of 
mortality  from  cholera  that  was  occurring  before  the 
eruption  took  place. 

"  With  regard  to  the  73  deaths  occurring  in  the  locality 
belonging,  as  it  were,  to  the  pump,  there  were  6 1. instances 
in  which  I  was  informed  that  the  deceased  persons  used 
to  drink  the  water  from  the  pump  in  Broad  Street,  either 
constantly  or  occasionally.  In  six  (6)  instances  I  could 
get  no  information,  owing  to  the  death  or  the  departure  of 
every  one  connected  with  the  deceased  individuals ;  and  in 
six  (6)  cases  I  was  informed  that  the  deceased  persons  did 
not  drink  the  pump  water  before  their  illness. 

"  The  result  of  the  inquiry  consequently  was  that  there 
had  been  no  particular  outbreak  or  increase  of  cholera  in 
this  part  of  London,  except  among  the  persons  who  were 
in  the  habit  of  drinking  the  water  of  the  above-mentioned 
pump  well. 

"  I  had  an  interview  with  the  Board  of  Guardians  of 
St.  James's  Parish  on  the  evening  of  Thursday,  7th  of  Sep- 
tember, and  represented  the  above  circumstances  to  them. 
In  consequence  of  what  I  said  the  handle  of  the  pump  was 
removed  on  the  following  day.  .  .  . 

"  The  additional  facts  that  I  have  been  able  to  ascertain 
are  in  accordance  with  those  above  related ;  and  as  regards 


ASIATIC   CHOLERA 

AISD 

THE  BROAD  STREET   PUMR 
LONDON  IS54. 


•LOCATION  OF  PUMPS. 
•  LOCATION  OF  FATAL  CHOLERA  CASES. 

—  —  BOUNDARY  Of  EQUAL  DISTANCES  BETWEEC 
BROAD  STREET  PUMP  AMD 
OTHER  PUMPS. 

(AFTER  THE  ORIGINAL  MAP  BY 

DR.    JOHN    SMOW.) 


ASIATIC   CHOLERA  AND   THE   BROAD   ST.   PUMP     175 

the  small  number  of  those  attacked  who  were  believed  not 
to  have  drunk  the  water  from  the  Broad  Street  pump,  it 
must  be  obvious  that  there  are  various  ways  in  which  the 
deceased  persons  may  have  taken  it  without  the  knowl- 
edge of  their  friends.  The  water  was  used  for  mixing 
with  spirits  in  some  of  the  public  houses  around.  It  was 
used  likewise  at  dining  rooms  and  coffee-shops.  The 
keeper  of  a  coffee-shop  which  was  frequented  by  me- 
chanics, and  where  the  pump  water  was  supplied  at  dinner 
time,  informed  me  on  the  6th  of  September  that  she  was 
already  aware  of  nine  of  her  customers  who  were  dead." 

On  the  other  hand,  Dr.  Snow  discovered  that  while  a 
workhouse  (almshouse)  in  Poland  Street  was  three-fourths 
surrounded  by  houses  in  which  cholera  deaths  occurred, 
out  of  535  inmates  of  the  workhouse  only  five  (5)  cholera 
deaths  occurred.  The  workhouse,  however,  had  a  well  of 
its  own  in  addition  to  the  city  supply,  and  never  sent  for 
water  to  the  Broad  Street  pump.  If  the  cholera  mortality 
in  the  workhouse  had  been  equal  to  that  in  its  immediate 
vicinity,  it  should  have  had  fifty  deaths. 

A  brewery  in  Broad  Street  employing  seventy  workmen 
was  entirely  exempt,  but  having  a  well  of  its  own,  and 
allowances  of  malt  liquor  having  been  customarily  made 
to  the  employees,  it  appeared  likely  that  the  proprietor  was 
right  in  his  belief  that  resort  was  never  had  to  the  Broad 
Street  well. 

It  was  quite  otherwise  in  a  cartridge  factory  at  No.  38 
Broad  Street,  where  about  two  hundred  work-people  were 
employed,  two  tubs  of  drinking  water  having  been  kept 
on  the  premises  and  always  filled  from  the  Broad  Street 
well.  Among  these  employees  eighteen  died  of  cholera. 
Similar  facts  were  elicited  for  other  factories  on  the  same 
street,  all  tending  to  show  that  in  general  those  who  drank 
the  water  from  the  Broad  Street  well  suffered  either  from 
cholera  or  diarrhoea,  while  those  who  did  not  drink  that 
water  escaped.  The  whole  chain  of  evidence  was  made 


176    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

absolutely  conclusive  by  several  remarkable  and  striking 
cases  like  the  following  :  — 

"  A  gentleman  in  delicate  health  was  sent  for  from 
Brighton  to  see  his  brother  at  No.  6  Poland  Street,  who 
was  attacked  with  cholera  and  died  in  twelve  hours,  on 
the  ist  of  September.  The  gentleman  arrived  after  his 
brother's  death,  and  did  not  see  the  body.  He  only 
stayed  about  twenty  minutes  in  the  house,  where  he  took 
a  hasty  and  scanty  luncheon  of  rump  steak,  taking  with 
it  a  small  tumbler  of  cold  brandy-and-water,  the  water 
being  from  Broad  Street  pump.  He  went  to  Pentonville, 
and  was  attacked  with  cholera  on  the  evening  of  the  fol- 
lowing day,  September  the  2d,  and  died  the  next  evening." 

"  The  deaths  of  Mrs.  E and  her  niece,  who  drank 

the  water  from  Broad  Street  at  the  West  End,  Hampstead, 
deserve  especially  to  be  noticed.  I  was  informed  by  Mrs. 
E 's  son  that  his  mother  had  not  been  in  the  neighbor- 
hood of  Broad  Street  for  many  months.  A  cart  went  from 
Broad  Street  to  West  End  every  day,  and  it  was  the  cus- 
tom to  take  out  a  large  bottle  of  the  water  from  the  pump 
in  Broad  Street,  as  she  preferred  it.  The  water  was  taken 
out  on  Thursday,  the  3ist  of  August,  and  she  drank  of  it 
in  the  evening  and  also  on  Friday.  She  was  seized  with 
cholera  on  the  evening  of  the  latter  day,  and  died  on  Sat- 
urday. A  niece  who  was  on  a  visit  to  this  lady  also  drank 
of  the  water;  she  returned  to  her  residence,  a  high  and 
healthy  part  of  Islington,  was  attacked  with  cholera,  and 
died  also.  There  was  no  cholera  at  this  time,  either  at 
West  End  or  in  the  neighborhood  where  the  niece  died. 
Besides  these  two  persons  only  one  servant  partook  of  the 
water  at  West  End,  Hampstead,  and  she  did  not  suffer,  or, 
at  least,  not  severely.  She  had  diarrhoea." 

Dr.  Snow's  inquiry  into  the  cases  of  cholera  which  were 
nearer  other  pumps  showed  that  in  most  the  victims  had 
preferred,  or  had  access  to,  the  water  of  the  Broad  Street 
well,  and  in  only  a  few  cases  was  it  impossible  to  trace 


ASIATIC   CHOLERA  AND   THE   BROAD   ST.   PUMP     177 


any  connection  with  that  pump.  Finally,  Dr.  Snow  made 
a  statistical  statement  of  great  value,  which  is  here  given 
in  its  original  form. 

THE   BROAD    STREET    (LONDON)    WELL   AND    DEATHS   FROM 
ASIATIC    CHOLERA   NEAR   IT   IN    1854 


DATE 

NUMBER 
OF  FATAL 
ATTACKS 

DEATHS 

DATE 

NUMBER 
OF  FATAL 
ATTACKS 

DEATHS 

August  19 

I 

I 

Sept.  II 

5 

15 

"    20 

I 

O 

"   12 

i 

6 

"    21 

I 

2 

«   ,.j 

3 

13 

"    22 

O 

0 

'   H 

o 

6 

"  23 

I 

0 

'  *5 

i 

8 

"  24 

I 

2 

«  16 

4 

6 

"  25 

O 

0 

'  17 

2 

5 

"  26 

I 

O 

«  18 

3 

2 

"  27 

I 

I 

'  19 

0 

3 

"  28 

I 

O 

"   20 

0 

o 

"  29 

I 

I 

"   21 

2 

o 

"   3° 

8 

2 

"   22 

2 

"  31 

56 

3 

"   23 

3 

Sept.  i 

143 

70 

"   24 

o 

"     2 

116 

127 

"   25 

o 

"   3 

54 

76 

"   26 

2 

4 

46 

7i 

"   27 

I 

O 

"   5 

36 

45 

"   28 

O 

2 

6 

20 

37 

"   29 

o 

O 

"   7 

28 

32 

"   30 

o 

O 

8 

«     n 

12 

30 

Date  unknown 

45 

0 

9 
"    10 

I  I 

5 

24 
18 

Total  .  . 

616 

616 

—  77z^   Rev.   Mr.     White/lead's   Detailed   Studies  of 
Broad  Street  and  Its  Pump 

In  addition  to  the  original  and  general  inquiry  conducted 
from  the  time  of  the  outbreak  by  Dr.  Snow,  the  Rev.  H. 
Whitehead,  M.A.,1  curate  of  St.  Luke's  in  Berwick  Street, 

1"The  Rev.  H.  Whitehead,  M.A.,  to  whom  medicine  is  in  a  great 
measure  indebted  for  that  elaborate  investigation  of  the  cholera  outbreak  in 
the  parish  of  St.  James,  Westminster  (the  Broad  Street  pump  outbreak), 
which  it  is  now  known  gives  to  Dr.  Snow's  opinion  of  its  origin  a  probability 


178     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

and  like  Dr.  Snow,  a  member  of  the  Cholera  Inquiry  Com- 
mittee, whose  knowledge  of  the  district  both  before  and 
during  the  epidemic,  owing  to  his  official  position,  gave 
him  unusual  advantages,  made  a  most  elaborate  and  pains- 
taking house-to-house  investigation  of  one  of  the  principal 
streets  affected,  viz.,  Broad  Street  itself.  Mr.  White- 
head's  report,  like  that  of  Dr.  Snow,  is  a  model  of  careful 
and  extended  observation  and  study,  cautious  generalizing 
and  rigid  verification.  It  is  an  excellent  instance  of  in- 
ductive scientific  inquiry  by  a  layman  in  sanitation.  Mr. 
Whitehead  found  the  number  of  houses  on  Broad  Street, 
49;  the  resident  householders,  35;  the  total  number  of 
resident  inhabitants,  896;  the  total  number  of  deaths 
among  these,  90.  Deaths  among  non-residents  (workmen, 
etc.)  belonging  to  the  street,  28.  Total  deaths  chargeable 
to  this  street  alone,  118.  Only  10  houses  out  of  49  were 
free  from  cholera.  The  dates  of  attack  of  the  fatal  cases 
resident  in  this  single  street  were  as  follows :  — 


DATE  OF  ATTACK 

NUMBER  OF 
FATAL  ATTACKS 

DATE  OF  ATTACK 

NUMBER  OF 
FATAL  ATTACKS 

Aug 
Se 

•USt   12 
28 
30 
31 
pt.      I 
2 

3 

I 
I 
I 
6 
26 
24 
9 

Sept.    4  . 

8 
6 

5 

0 

2 
I 

c  . 

§:  .  :  :  : 

•j  

8  

9  

90 

Mr.  Whitehead's  detailed  investigation  was  not  made 
until  the  spring  of  1855,  but  in  spite  of  this  fact  it  supplied 
most  interesting  and  important  confirmatory  evidence  of 
Dr.  Snow's  theory  that  the  Broad  Street  well  was  the  source 
of  the  epidemic.  Mr.  Whitehead,  moreover,  went  further 

practically  amounting  to  a  demonstration." — MR.  J.  NETTEN  RADCLIFFE, 
"On  Cholera  in  London  in  1 866,"  Ninth  Rep.  Med.  Officer  of  the  Privy 
Council,  p.  288. 


DRINKING  WATER  AND   ASIATIC   CHOLERA       179 

than  Dr.  Snow,  and  endeavored  to  find  out  how  the  well 
came  to  be  infected,  why  its  infectious  condition  was  so 
limited  as  it  appeared  to  have  been,  and  to  answer  various 
other  questions  which  occurred  hi  the  course  of  his  inquiry. 
As  a  result,  he  concluded  that  the  well  must  have  been 
most  infected  on  August  3 1 ;  that  for  some  reason  unknown 
a  partial  purification  began  on  September  2,  and  thereafter 
proceeded  rapidly.  There  was  some  evidence  that  on  Aug- 
ust 30  the  water  was  much  less  infected  than  on  the  3ist, 
so  that  its  dangerous  condition  was  apparently  temporary 
only.  He  further  discovered  that  in  the  house  No.  40 
Broad  Street,  which  was  the  nearest  house  to  the  well,  there 
had  been  not  only  four  fatal  cases  of  cholera  contempora- 
neous with  the  epidemic,  but  certain  earlier  cases  of  an 
obscure  nature,  which  might  have  been  cholera,  and  that 
dejecta  from  these  had  been  thrown  without  disinfection  into 
a  cesspool  very  near  to  the  well.  On  his  reporting  these 
facts,  in  April,  1855,  to  the  main  committee,  Mr.  J.  York, 
secretary  and  surveyor  to  the  committee,  was  instructed  to 
survey  the  locality  and  examine  the  well,  cesspool  and 
drains  at  No.  40  Broad  Street 

(«?)    Survey  and  Description  of  the  Broad  Street   Well 
and  its  Surroundings 

Mr.  York's  report  revealed  a  startling  condition  of  af- 
fairs. The^well  was  circular  in  section,  28  ft.  10  in.  deep, 
6  ft  in  diameter,  lined  with  brick,  and  when  examined  con- 
tained 7  ft.  6  in.  of  water.  It  was  arched  in  at  the  top, 
dome  fashion,  and  tightly  closed  at  a  level  3  ft.  6  in.  below 
the  street,  by  a  cover  occupying  the  crest  of  the  dome. 

The  bottom  of  the  main  drain  of  the  house  No.  40  Broad 
Street  lay  9  ft.  2  in.  above  the  water  level,  and  one  of  its 
sides  was  distant  from  the  brick  lining  of  the  well  only  2  ft. 
8  in.  It  was  — 

"constructed  on  the  old-fashioned  plan  of  a  flat  bottom,  12  in.  wide, 
with  brick  sides  rising  about  12  in.  high,  and  covered  with  old  stone. 


180    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

As  this  drain  had  but  a  small  fall,  or  inclination  outward  to  the  main 
sewer,  the  bottom  was  covered  with  an  accumulation  of  soil  deposit 
about  2  in.  thick ;  and  upon  clearing  this  soil  away  the  mortar  joints 
of  the  old  stone  bottom  were  found  to  be  perished,  as  was  also  all  the 
jointing  of  the  brick  sides,  which  had  brought  the  brick  work  into  the 
condition  of  a  sieve,  and  through  which  the  house  drainage  water 
must  have  percolated  for  a  considerable  period.  .  .  . 

"  After  opening  back  the  main  drain,  a  cesspool  intended  for  a  trap, 
but  misconstructed,  was  found  in  the  area,  3  ft.  8  in.  long,  by  2  ft.  6  in. 
wide,  and  3  ft.  deep ;  and  upon  or  over  a  part  of  this  cesspool  a  com- 
mon open  privy  (without  water  supply),  for  the  use  of  the  house,  was 
erected,  the  cesspool  being  fully  charged  with  soil.  This  privy  was 
formed  across  the  east  end  of  the  area,  and  upon  removing  the  soil  the 
brickwork  of  the  cesspool  was  found  to  be  in  the  same  decayed  condi- 
tion as  the  drain,  and  which  may  be  better  comprehended  by  stating 
that  the  bricks  were  easily  lifted  from  their  beds  without  any,  the  least, 
force ;  so  that  any  fluid  could  readily  pass  through  the  work,  or,  as  was 
the  case  when  first  opened,  over  the  top  course  of  bricks  of  the  trap, 
into  the  earth  or  made  ground  immediately  under  and  adjoining  the  end 
wall  eastward,  this  surface  drainage  being  caused  by  the  accumulation 
of  soil  in,  and  the  misconstruction  of,  the  cesspool.  .  .  . 

"  Thus,  therefore,  from  the  charged  condition  of  the  cesspool,  the 
defective  state  of  its  brickwork,  and  also  that  of  the  drain,  no  doubt  re- 
mains upon  my  mind  that  constant  percolation,  and  for  a  considerable 
period,  had  been  conveying  fluid  matter  from  the  drains  into  the  well ; 
but  lest  any  doubt  should  arise  upon  this  subject  hereafter,  I  had  two 
spaces  of  the  brick  steining,  2  ft.  square  each,  taken  out  of  the  inside 
of  the  well  —  the  first  13  ft.  deep  from  the  level  of  the  street  paving, 
the  second  18  ft.  deep,  and  a  third  was  afterward  opened  still  lower, 
when  the  washed  appearance  of  the  ground  and  gravel  fully  corroborated 
the  assumption.  In  addition  thereto,  the  ground  was  dug  out  between 
the  cesspool  and  the  well  to  3  ft.  below  the  bottom  of  the  former, 
and  its  black,  saturated,  swampy  condition  clearly  demonstrated  the 
fact,  as  did  also  the  small  furrowed  appearance  of  the  underlying  gravel 
observed  from  the  inside  of  the  well,  from  which  the  fine  sand  had  been 
washed  away  during  the  process  of  filtration."  —  Report  of  J.  York, 
Secretary  and  Surveyor  to  ttie  Cholera  Inquiry  Committee.  — L.  c. 

It  was  thus  established,  as  clearly  as  can  be  done  by 
circumstantial  evidence,  that  the  great  epidemic  in  St. 
James'  Parish,  Westminster,  London,  in  1854,  was  caused 
by  the  polluted  water  of  the  Broad  Street  well,  which  for  a 


PAVEMENT. 


I      ft 


7  a 

~<°  -I 

11 


L. 


w 


WATER      LINE. 


ASIATIC    CHOLERA 

AND 

THE   BROAD  STREET  WELL. 

LONDON    1654. 

W. .WELL. 

D._ MAIN  DRAIN  Or  HOUSE  NO. 40. 

VANDV.*  .CELLARS   UNDER  STREET. 
C. CESSPOOL. 

P PRIVY. 

(AFTER  MR.  YORkfe  ORIGINAL  DRAWINGS.) 


ASIATIC  CHOLERA  AND  THE  BROAD  ST.  WELL     l8l 

very  few  days  was  probably  infected  with  cholera  germs. 
It  is  much  less  clear  how  the  well  became  infected,  but  it 
seems  probable  that  the  dejecta  of  a  cholera  patient  found 
tolerably  direct  access  to  the  well  from  the  cesspool  or 
drain  of  a  house  near  by.  There  is  no  evidence  whatever 
that  the  germs  multiplied  in  the  well,  but  rather  much 
evidence  that  they  rapidly  died  out.  It  is  repeatedly  stated 
in  the  report  that  the  water  was  preferred  for  drinking 
because  it  was  "  cold,"  i.e.  colder  than  the  cistern  water 
derived  from  the  public  water  supply,  and  this  condition 
would  probably  favor  such  dying  out. 

That  the  water  had  long  been  polluted,  there  can  be  no 
doubt.  There  was  evidence  of  this,  and  also  some  evidence 
that  it  was  worse  than  usual  at  the  time  when  it  was  prob- 
ably infected.  One  consumer  spoke  of  it  as  having  been 
at  that  time  "  offensive  "  in  taste  or  odor.  It  is  instructive 
to  note  that  mere  pollution  seems  to  have  done  no  obvi- 
ous harm.  Specific  infection,  however,  produced  Asiatic 
cholera. 

Mr.  Whitehead,  in  his  singularly  fair  and  candid  report, 
raises  an  interesting  question,  viz.,  why,  if  an  early  and 
unrecognized  case  in  the  house*in  question  brought  about 
infection  of  the  well,  should  not  the  four  severer  cases  of 
undoubted  cholera  subsequently  in  the  same  house,  with 
no  known  change  in  the  drainage,  have  produced  even 
greater  disaster  ?  This  question  remains  unanswered,  ex- 
cept that  after  the  removal  of  the  pump  handle  on  the 
8th  of  September  access  to  the  well  was  shut  off,  and 
during  the  intermediate  week  the  well  may  have  been 
avoided  by  the  frightened  people ;  or,  owing  to  illness,  less 
water  may  have  been  used  in  No.  40  Broad  Street,  so 
that  the  cesspool  did  not  overflow ;  or  some  other  condi- 
tion, unknown,  may  have  been  changed. 


1 82     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

§  5. — An  Epidemic  of  Asiatic  Cholera  in  London  in  1866 
traced  to  a  Polluted  and  Infected  Surface  Water  Supply 

Dr.  John  Snow,  in  1854,  gave  it  as  his  opinion  that  not 
only  wells  but  also  public  water  supplies  of  far  more  gen- 
eral distribution,  such  as  those  furnished  by  cities  or  cor- 
porations and  derived  from  rivers,  may,  under  certain 
circumstances,  be  carriers  of  cholera.  The  great  epidemics 
of  Asiatic  cholera  in  London  in  1832,  1848-1849  and 
1853-1854  had  so  strongly  enforced  this  idea  that  in  deal- 
ing with  an  important  problem  raised  by  epidemic  cholera 
in  London  in  1866  Mr.  J.  Netten  Radcliffe  states  that, 
"The  predominant  lesson  derived  from  the  outbreaks  of 
1848-1849  and  1853-1854  was  that  the  localities  of  chief 
prevalence  of  the  disease  were  mainly,  if  not  solely,  de- 
termined by  the  degree  of  impurity  of  the  water  supply." 1 

In  1866  Asiatic  cholera,  having  again  become  epidemic 
in  London,  appeared  in  marked  abundance  in  certain 
eastern  districts  of  the  city.  A  special  investigation  of 
its  origin  and  distribution  in  those  parts  was  made  for  the 
medical  officer  of  the  Privy  Council  (Mr.,  afterward  Sir, 
John  Simon),  by  Mr.  J.  Netten  Radcliffe,  whose  very  elabo- 
rate and  painstaking  report  (published  in  extenso  in  the 
Ninth  Report,  London,  1867)  served  to  fasten  the  blame 
for  the  excess  in  East  London  upon  a  special  pollution  and 
infection  of  a  portion  of  the  public  water  supply  of  the 
district,  derived  from  the  river  Lea.2 

Briefly  stated,  it  may  be  said  that  the  epidemic  of  1866 

1  Ninth  Rep.  Med.  Officer  of  the  Privy  Council,  p.  295.  See  also  Simon, 
Report  on  the  Cholera  Epidemics  of  London  in  1848-1849  and  1853-1854 
as  affected  by  the  Consumption  of  Impure  Water.  London,  1856. 

*  Like  some  more  recent  students  of  English  sanitation,  Mr.  Radcliffe 
seems  to  have  been  puzzled  in  regard  to  the  correct  spelling  of  this  word. 
His  note  on  the  subject  is  therefore  interesting.  "The  Rivers  Pollution  Com- 
missioners have  spelled  the  name  of  this  river  Lee.  All  the  standard  maps 
and  geographical  works  of  reference  spell  the  name  Lea.  I  have  adhered  to 
the  orthography  commonly  used."  —  Op.  cit.,  p.  280. 


ASIATIC   CHOLERA   IN   LONDON   IN    1866 


183 


in  England  began  on  April  28  with  a  case  in  Bristol 
imported  from  "Rotterdam.  By  May  1 5  the  disease  was 
prevailing  among  certain  emigrants  on  board  ships  in  the 
Mersey  bound  for  New  York.  These  emigrants  had  re- 
cently come  from  infected  places  on  the  continent.  Scat- 
tered cases  or  outbreaks  sonn  began  to  be  reported  from 
various  parts  of  England,  such  as  Swansea  and  South- 
ampton. The  first  death  reported  in  London,  according 
to  Mr.  Simon,  was  on  July  18,  and  two  days  later  an 
alarming  number  of  cases  appeared  in  East  London. 
By  July  21  it  was  clear  that  a  special  epidemic  was  pre- 
vailing in  that  region,  and  it  is  this  special  outbreak  or 
"explosion"  of  cholera  which  forms  the  subject  of  Mr. 
Radcliffe's  report.  During  the  three  months,  —  July, 
August  and  September,  —  there  were  registered  in  all 
England  10,365  deaths  from  cholera  and  9570  deaths 
from  diarrhoea.  During  the  seven  days  ending  August  4 
there  were  in  London  alone  1053  deaths  from  cholera,  and 
on  one  day  (August  i)  204.  The  following  comparison 
given  by  Mr.  Radcliffe  of  the  duration  and  mortality  of 
the  cholera  epidemics  in  London  in  1849,  1854,  and  1866 
is  noteworthy :  — 


Epidemic 

Deaths  from 

Ratio  to  10,000 

Deaths  from 

Ratio  to  10,000 

of 

Cholera 

Inhabitants 

Diarrhoea 

Inhabitants 

1849 

23  weeks 

13,565 

51 

2926 

13.0 

1854 

23  weeks 

10,684 

43 

2551 

10.  1 

1866 

23  weeks 

5.548 

18 

2692 

8.8 

"  Cholera  having  been  so  less  fatal  in  proportion  to  the 
number  of  persons  attacked  by  the  disease  [in  1866]  .  .  . 
the  foregoing  results  would  indicate  increased,  and  perhaps 
increasing,  safeguards  in  the  metropolis."  —  Op.  cit.,  p.  277. 
Mr.  Radcliffe's  investigation  soon  showed,  however,  that 
further  safeguards,  at  least  in  respect  to  water  supply, 
were  urgently  needed. 


1 84    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

Of  the  whole  number  of  cholera  deaths  (5548),  3909  oc- 
curred in  the  east  districts — "more  than  double  the  amount 
distributed  over  the  rest  of  the  metropolis."  Moreover,  it 
was  in  these  districts  that  it  increased  most  rapidly  and 
to  the  highest  point,  and  that  it  fell  off  afterward  most 
quickly.  Again,  "no  relative  development  of  like  magni- 
tude, suddenness,  and  shortness  of  duration  had  occurred 
in  previous  outbreaks  of  cholera  in  the  metropolis,"  either 
in  these  or  other  districts.  The  brunt  of  the  malady  in 
1849  and  1854  had  fallen  upon  the  south  districts. 

"  London  was  unquestionably  less  filthy  at  the  time  of 
the  outbreak  than  in  any  previous  outbreak.  But  the  east 
districts  could  not  claim  a  preeminence  of  filth.  In  the 
west  of  the  metropolis  and  south  of  the  river  there  were 
many  localities  as  filthy.  Neither  Rotherhithe,  nor  Ber- 
mondsey,  nor  South wark,  nor  Westminster,  can  be  compared 
favorably  with  the  east  of  London,  yet  the  three  former 
places  suffered  in  a  trifling  degree  as  compared  with  the 
latter."  —  Op.  cit.,  p.  293. 

Mr.  Radcliffe  carefully  considered,  in  addition  to  "filth," 
such  possible  or  supposed  causes  of  cholera  as  "soil," 
"  density  of  population,"  "  sewerage,"  "  locality,"  "  meteor- 
ological states"  and  "altitude,"  and  concluded  that  "not 
one  of  the  conditions  named  .  .  .  and  believed  to  be  liable 
to  affect  the  progress  and  development  of  epidemic  cholera, 
the  disease  being  present,  will  account  for  more  than  very 
limited  fluctuations  of  the  outbreak,  or  for  its  localization 
in  any  particular  spot  in  a  restricted  degree  only.  Any 
combination  of  these  conditions  is,  moreover,  equally  inef- 
ficacious in  explaining  the  peculiar  localization  and  fluctua- 
tion in  the  east  districts  of  the  metropolis." 

(a) — Suspicion  directed  to   the  Public   Water  Supply  of 
the  Infected  District 

The  water  supply  alone  remained  to  be  considered,  and 
"  from  the  commencement  of  the  localization  of  cholera  in 


ASIATIC   CHOLERA  IN   LONDON   IN   1866  185 

the  east  districts  the  probable  association  of  this  circum- 
scription with  an  impure  water  supply  was  forced  upon  the 
mind.  .  .  .  During  the  week  ending  the  28th  of  July  it 
became  obvious  that  the  brunt  of  the  outbreak  had  fallen 
upon  the  east  districts;  and  in  the  bill  of  mortality  for 
the  week  the  registrar  general  directed  attention  to  the 
fact  that  the  field  of  prevalence  of  the  disease  was  supplied 
with  water  from  the  East  London  Water  Company's  works." 
On  August  i  the  water  company  was  notified  that  its 
supply  was  under  suspicion,  and  the  local  sanitary  author- 
ities were  recommended  by  Mr.  Simon  to  issue  the 
following :  — 

CHOLERA.      NOTICE  ! 

"  The  inhabitants  of  the  District  within 
which  Cholera  is  prevailing  are  earnestly 
advised  not  to  drink  any  water  which  has 
not  previously  been  boiled.  ..." 

NM 

Further  investigation  satisfied  Mr.  Radcliffe  that  the 
"explosion"  of  cholera,  which  occurred  just  prior  to  July 
21,  had  its  origin  in  a  temporary  and  limited  infection  of 
one  portion  of  the  East  London  Company's  waterworks 
situated  at  Old  Ford,  on  the  river  Lea.  This  river,  con- 
siderably polluted  by  sewage  in  its  upper  reaches,  was 
subjected  to  subsidence  and  filtration  above,  and  at,  Lea 
Bridge,  respectively.  Some  of  the  filtered  water  was  dis- 
tributed from  this  point,  and  no  blame  was  attached  to  this 
portion  of  the  supply.  The  remainder  was  conveyed 
farther  into  the  metropolis  by  a  closed  iron  conduit,  to  two 
covered  reservoirs  on  the  west  bank  of  the  Lea  at  Old  Ford, 
and  from  this  point  pumped  into  the  distributing  mains. 
On  the  east  side  of  the  river  at  Old  Ford  were  two  uncov- 
ered reservoirs  of  large  capacity,  one  of  which  had,  at  the 
time  of  the  outbreak,  direct  connection  with  the  covered 
reservoirs  of  filtered  water.  The  open  reservoirs  were  also 


1 86     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

connected  with  the  filtering  beds  at  Lea  Bridge  by  an  open 
and  foul  conduit,  and  they  sometimes  received  the  waste 
water  from  them  unfiltered.  They  seem  to  have  served  as 
a  reserve  of  unfiltered  water  to  draw  upon  in  case  of  clog- 
ging of  the  filter  beds  or  in  case  of  fire. 

It  was  admitted  that  the  filter  beds  had,  in  fact,  been 
seriously  clogged  just  before  the  cholera  outbreak,  and  it 
was  in  evidence  that  on  at  least  one  occasion,  early  in 
July,  some  300,000  gallons  of  unfiltered  water  had  been 
drawn  from  one  of  the  uncovered  reservoirs  into  the  cov- 
ered reservoirs,  to  make  good  a  deficiency  in  filtered  water 
due  to  clogging  of  the  filters.  Precisely  how  this  unfil- 
tered and  impure  water  may  have  become  infected  by 
choleraic  poison  is  not  known.  Mr.  Radcliffe  believed 
that  soakage  from  the  river,  which  was  known  to  have 
been  infected  in  its  lower  reaches,  probably  found  access 
to  the  open  reservoir.  This  is  certainly  possible,  but  it 
seems  more  likely  that  the  infection  may  have  found 
direct  access  to  the  river  in  the  unpurified  sewage  of  some 
city  or  town  on  the  upper  watershed  above  the  point  of 
intake  of  the  East  London  Company's  works.  "  In  its 
course  it  (the  river  Lea)  drains  about  570  square  miles  of 
country,  and  before  reaching  Enfield  Lock  ...  it  receives 
the  sewage  of  upward  of  1 50,000  souls.  It  receives  in  its 
course,  also,  as  affluents,  several  smaller  streams,  each  in 
its  degree  a  recipient  of  sewage."  —  Op.  cit.y  p.  296. 

The  medical  officer  of  the  Privy  Council,  in  his  historical 
summary  of  the  progress  of  the  disease  in  England,  states 
that  even  "within  the  next  few  days"  after  May  15  two 
cases  were  reported  at  Swansea,  "  and  single  cases  in  vari- 
ous other  parts  of  the  country."  Of  early  July  he  writes, 
"  evidently  England  was  now  being  infected  in  many  dif- 
ferent directions.  Reports  of  new  centres  of  infection 
became  more  and  more  frequent."  It  is  not  difficult  to 
suppose  that  some  one  or  more  obscure  case,  or  cases,  may 
have  occurred  at  this  time  or  afterward  upon  the  watershed 


TYPHOID  FEVER   IN   LAUSEN,   SWITZERLAND      187 

of  the  Lea,  and  thus  have  directly  infected  that  river,  pol- 
luted as  it  plainly  was  with  unpurified  sewage. 

(#) —  The   Obvious    Value  of  Filtration  as  a  Sanitary 
Safeguard 

On  any  hypothesis  the  supreme  value  and  importance 
of  filtration  became  manifest,  for  it  was  evidently  only  the 
unfiltered  river  water  which  did  harm.  The  supply  pumped 
from  Lea  Bridge  was  of  filtered  water  derived  from  a  highly 
polluted,  and  probably  infected,  river,  and  yet  seems  to 
have  caused  no  spread  of  the  disease. 

This  apparently  logical  conclusion  as  to  the  value  of  ni- 
tration was,  nevertheless,  laid  open  to  serious  question  a 
few  years  later,  in  consequence  of  the  famous  Lausen 
epidemic,  to  a  consideration  of  which  we  may  now  turn. 

§  6.  — An  Epidemic  of  Typhoid  Fever  in  Lausen^  Switzer- 
land, due  to  an  Infected  Ground  Water  or  Spring 

Typhoid  fever  derived  from  impure  drinking  water  is  now 
recognized  as  of  common  occurrence,  and  a  great  number 
of  destructive  epidemics  have  been  traced  to  this  source. 
The  first  to  attract  universal  attention  was  that  which 
occurred  in  Lausen,  Switzerland,  in  1872;  and  because  of 
certain  peculiar  conditions  connected  with  it,  and  especially 
because  of  its  influence  upon  the  theory  and  practice  of  the 
purification  of  water  by  filtration,  it  deserves  the  most  care- 
ful consideration  by  all  students  of  sanitation. 

The  epidemic  occurred  in  the  little  village  of  Lausen  in 
the  canton  of  Basel  in  Switzerland  in  August,  1872. 
Lausen  was  a  well-kept  village  of  90  houses  and  780 
inhabitants,  and  had  never,  so  far  as  known,  suffered 
from  a  typhoid  epidemic.  For  many  years  it  had  not 
had  even  a  single  case  of  typhoid  fever,  and  it  had 
escaped  the  cholera  even  when  the  surrounding  country 
suffered  from  it  Suddenly,  in  August,  1872,  an  outbreak 


1 88     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

of  typhoid  fever  occurred,  affecting  a  large  part  of  the 
entire  population. 

A  short  distance  south  of  Lausen  was  a  little  valley,  the 
Furlerthal,  separated  from  Lausen  by  a  hill,  the  Stockhal- 
den,  and  in  this  valley,  on  June  19,  upon  an  isolated  farm, 
a  peasant,  who  had  recently  been  away  from  home,  fell  ill 
with  a  very  severe  case  of  typhoid  fever,  which  he  had 
apparently  contracted  during  his  absence.  In  the  next 
two  months  there  occurred  three  other  cases  in  the  neigh- 
borhood, —  a  girl,  and  the  wife  and  the  son  of  the  peasant. 

No  one  in  Lausen  knew  anything  of  these  cases  in  the 
remote  and  lonely  valley  when  suddenly,  on  August  7,  ten 
cases  of  typhoid  fever  appeared  in  Lausen,  and  by  the  end 
of  nine  days,  fifty-seven  cases.  The  number  rose  in  the 
first  four  weeks  to  more  than  one  hundred,  and  by 
the  end  of  the  epidemic  in  October  to  about  130,  or 
seventeen  per  cent  of  the  population.  Besides  these, 
fourteen  children  who  had  spent  their  summer  vacation  in 
Lausen  fell  ill  with  the  same  disease  in  Basel.  The  fever 
was  distributed  quite  evenly  throughout  the  town,  with  the 
exception  of  certain  houses  which  derived  their  water  from 
their  own  wells  and  not  from  the  public  water  supply. 
Attention  was  thus  fixed  upon  the  latter,  which  was  obtained 
from  a  well  or  spring  at  the  foot  of  the  Stockhalden  hill  on 
the  Lausen  side.  The  well  was  walled  up,  covered  and  ap- 
parently protected,  and  from  it  the  water  was  conducted  to 
the  village,  where  it  was  distributed  by  several  public  foun- 
tains. Only  six  houses  used  their  own  wells,  and  in  these  six 
there  was  not  a  single  case  of  typhoid  fever,  while  in  almost 
all  the  other  houses  of  the  village,  which  depended  upon  the 
public  water  supply,  cases  of  the  disease  existed.  Suspicion 
was  thus  directed  to  the  water  supply  as  the  source  of  the 
typhoid  poison,  very  largely  because  no  other  source  could 
well  be  imagined.  A  distribution  of  the  disease  from  the 
farm  through  the  air  was  hardly  conceivable  because  houses 
in  the  Furlerthal,  although  lying  upon  the  same  plateau  and 


TYPHOID   FEVER   IN   LAUSEN,   SWITZERLAND     189 

naturally  more  accessible  through  the  atmosphere,  remained 
free  from  the  disease,  a  fact  which  seemed -to  prove  that  the 
infected  farmhouse  could  not  have  communicated  the  dis- 
ease to  Lausen  either  through  the  ground  water  or  through 
the  air. 

In  order,  however,  to  clinch  the  evidence  that  the  Lausen 
water  supply  had  been  infected,  it  became  desirable  to  show 
some  source  from  which  an  infection,  so  unusual  and  re- 
markable, could  have  come,  and  precisely  how  it  had  hap- 
pened. There  had  long  been  a  belief  that  the  Lausen  well 
or  spring  was  fed  by  and  had  a  subterranean  connection 
with  a  brook  (the  Fiirler  brook)  in  the  neighboring  Purler 
valley ;  and  since  this  brook  ran  near  the  peasant's  house 
and  was  known  to  have  been  freely  polluted  by  the  excreta 
of  the  typhoid  fever  patients,  absolute  proofs  of  the  connec- 
tion between  the  well  of  Lausen  and  the  Fiirler  brook  could 
not  fail  to  be  highly  suggestive  and  important.  Fortunately 
such  proofs  were  not  far  to  seek.  Some  ten  years  before, 
observations  had  been  made  which  had  showed  an  intimate 
connection  between  the  brook  and  the  well.  At  that  time, 
without  any  known  reason,  there  had  suddenly  appeared 
near  the  brook  in  the  Fiirler  valley  below  the  hamlet,  a  hole 
about  eight  feet  deep  and  three  feet  in  diameter,  at  the  bot- 
tom of  which  a  considerable  quantity  of  clear  water  was 
flowing.  As  an  experiment,  the  water  of  the  little  Fiirler 
brook  was  at  that  time  turned  into  this  hole,  with  the  result 
that  it  had  all  flowed  away  underground  and  disappeared, 
and  an  hour  or  two  later  the  public  fountains  of  Lausen 
which,  on  account  of  the  dry  weather  prevailing  at  the  time, 
were  barely  running,  had  begun  flowing  abundantly.  The 
water  from  them,  which  was  at  first  turbid,  later  became 
clear  ;  and  they  had  continued  to  flow  freely  until  the  Fiirler 
brook  was  returned  to  its  original  bed  and  the  hole  had 
been  filled  up.  But  every  year  afterward,  whenever  the 
meadows  below  the  site  of  the  hole  were  irrigated  or  over- 
flowed  by  the  waters  of  the  brook,  the  Lausen  fountains 


190     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

soon  began  to  flow  more  freely.  In  the  epidemic  year 
(1872)  the  meadows  had  been  overflowed  as  usual  from 
the  middle  to  the  end  of  July,  which  was  the  very  time 
when  the  brook  had  been  infected  by  the  excrements  of 
the  typhoid  patients.  The  water  supply  of  Lausen  had  in- 
creased as  usual,  had  been  turbid  at  the  beginning  and 
had  had  a  disagreeable  taste.  And  about  three  weeks 
after  the  beginning  of  the  irrigation  of  the  Fiirler  meadows, 
typhoid  fever  had  broken  out,  suddenly  and  violently,  in 
Lausen. 

In  order  to  make  matters,  if  possible,  more  certain,  the 
following  experiments  were  made,  but  unfortunately  not 
until  the  end  of  August  when  the  water  of  the  Lausen 
supply  had  again  become  clear.  The  hole  which  had 
appeared  ten  years  earlier,  and  had  afterward  been  filled 
up,  was  reopened,  and  the  little  brook  was  once  more  led 
into  it;  three  hours  later  the  Lausen  fountains  were 
yielding  double  their  usual  volume.  A  quantity  of  brine 
containing  about  eighteen  hundred  pounds  of  common 
salt  was  now  poured  into  the  brook  as  it  entered  the  hole, 
whereupon  there  appeared  very  soon  in  the  Lausen  water, 
first  a  small,  later  a  considerable  and  finally  a  very  strong, 
reaction  for  chlorine,  while  the  total  solids  increased  to 
an  amount  three  times  as  great  as  before  the  brine  was 
added.  In  another  experiment,  five  thousand  pounds  of 
flour  (Mehl\  finely  ground,  were  likewise  added  to  the 
brook  as  it  disappeared  in  the  hole ;  but  this  time  there  was 
no  increase  of  the  total  solids,  nor  were  any  starch  grains 
detected  in  the  Lausen  water. 

It  was  naturally  concluded  from  these  experiments  that 
while  the  water  of  the  brook  undoubtedly  passed  through 
to  Lausen  and  carried  with  it  salts  in  solution,  it  neverthe- 
less underwent  a  filtration  which  forbade  the  passage  of 
suspended  matters  as  large  as  starch  grains.  Dr.  Hagler, 
from  whose  report  the  foregoing  facts  are  taken,  was  careful, 
however,  to  state  that  "  it  is  not  denied  that  small  organized 


TYPHOID  FEVER  IN   LAUSEN,   SWITZERLAND     191 

particles,  such  as  typhoid  fever  germs,  may  nevertheless 
have  been  able  to  find  a  passage."  As  a  matter  of  fact  Dr. 
Hagler's  minute  account  does  to-day  give  us  some  indication 
that  such  germs  might  easily  have  passed  from  the  brook  to 
Lausen,  for  the  turbidity  of  which  he  repeatedly  speaks  is 
evidence  of  the  passage  of  particles  probably  as  small  as, 
and  possibly  smaller  than,  the  germs  of  typhoid  fever. 
(  Typhus  und  Trinkwasser,  Vierteljahrschrift  fur  offentliehe 
Gesundheitspflege,  FT,  154;  also  Sixth  Report,  Rivers  Pol- 
lution Commission  of  1868.  London,  1874.) 

Unfortunately,  this  was  before  pure  cultures  of  bacteria 
were  known,  and  no  experiments  were  made  with  suspended 
matters  as  small  as  bacteria.  The  conclusion  was  inevi- 
table that  although  filtration  had  in  this  case  sufficed  to 
remove  starch  grains,  it  had  been  powerless  to  remove  the 
germs  of  typhoid  fever;  and,  accordingly,  filtration  as  a 
safeguard  against  disease  in  drinking  water  fell  for  a  time 
into  disrepute.1 

§  7.  — An  Epidemic  of  Typhoid  Fever  in  Caterham  and 
Red  Hill  {England)  traced  to  a  Polluted  and  Infected 
Ground  Water  Supply 

A  number  of  epidemics  of  typhoid  fever  had  been  already 
traced  with  more  or  less  certainty  to  polluted  water  supplies 
when,  in  jj$£2,  there  appeared  a  serious  outbreak  of  this 
disease  in  the  towns  of  Caterham  and  Red  Hill  in  England. 
The  duty  of  investigation  of  this  case  was  fortunately  as- 
signed to  Dr.  Thorne-Thorne,  and  his  report  which  appears 
in  the  Report  of  the  Medical  Officer  of  the  Local  Govern- 
ment Board  for  1879,  pp.  78-92,  is  a  model  of  careful 
investigation  and  sound  reasoning.  Briefly  summarized, 
it  was  as  follows :  The  total  number  of  cases  affected 

1  See  a  paper  by  the  author  on  The  Rise  and  Progress  of  Water-Supply 
Sanitation  in  the  Nineteenth  Century.  Journal  New  England  Water  Works 
Association,  XV  (1901),  p.  330,  No.  4. 


192     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

during  the  epidemic  proper  was  352.  The  total  number 
of  deaths,  21.  The  disease  was  typical  typhoid  fever,  the 
patients  exhibiting  the  characteristic  rose-spots  and  diar- 
rhoea and  some  of  them  suffering  from  severe  pulmonary 
and  intestinal  complications,  the  latter  including  perfora- 
tion of  the  bowels  which,  in  four  cases,  was  the  immediate 
cause  of  death.  The  first  person  attacked  sickened  on 
January  19,  1879;  a  second,  on  the  2Oth;  two  more  on 
the  23d;  three  on  the  24th,  and  thenceforward  up  to  Feb- 
ruary 2,  to  which  date  information  was  at  first  limited, 
fresh  attacks  in  fresh  houses  occurred  day  by  day. 

Caterham  lies  in  the  rural  sanitary  district  of  Godstone, 
and  had  a  population  of  about  580x3.  It  included  at  this 
time  a  portion  called  Lower  Caterham,  near  the  head  of  the 
Caterham  valley,  a  valley  bounded  by  chalk  hills.  The 
houses  in  this  part  consisted  mainly  of  superior  villa  resi- 
dences. The  other  or  upper  part  lies  at  a  higher  altitude. 
Here,  also,  are  a  number  of  villas,  one  of  the  asylums  be- 
longing to  the  Metropolitan  District  Asylums  Board,  and 
certain  barracks. 

The  cases  of  typhoid  fever  referred  to,  and  which  had 
occurred  in  the  fortnight  ending  February  2,  were 
spread  over  a  very  wide  area,  some  in  Upper  and  some  in 
Lower  Caterham,  extending  to  the  extreme  outskirts  of 
both  places.  The  families  attacked  belonged  to  no  special 
class,  both  rich  and  poor  having  suffered.  It  was  appar- 
ent that  the  disease  could  not  have  been  conveyed  by 
means  of  any  general  system  of  sewers  for  the  majority  of 
the  houses  drained  into  separate  cesspools.  There  was 
also  no  possibility  that  there  had  been  any  common  cause 
of  infection  in  connection  with  the  prevailing  means  of 
excrement  disposal,  because  there  was  nothing  in  common 
with  regard  to  such  disposal.  The  possibility  of  infection 
by  means  of  milk  supply  was  next  inquired  into,  but  dis- 
proved. It  was  also  evident  that  personal  infection  could 
not  in  any  way  have  led  to  the  outbreak.  Finally,  it  was 


TYPHOID  FEVER  IN  CATERHAM,  ENGLAND   193 

stated  that  for  some  years  past  the  locality  had  been 
remarkably  free  from  the  disease,  and  only  one  isolated 
case  could  be  heard  of  as  having  occurred  during  the 
twelve  months  preceding  the  outbreak,  and  this  case  was 
believed  to  have  been  imported. 

Caterham  was  supplied  with  water  by  the  Caterham 
Waterworks  Company,  and  of  the  forty-seven  persons 
attacked  during  the  fortnight  in  question,  forty-five  re- 
sided in  houses  supplied  with  this  water.  Suspicion 
was  thus  directed  to  the  water  supply,  and  was  confirmed 
when  it  was  ascertained  that  the  two  remaining  patients, 
though  living  on  premises  having  private  wells,  had  been 
in  the  habit  of  spending  the  day  at  houses  supplied 
with  the  company's  water,  and  had  admittedly  used  this 
water. 

It  further  appeared  that  in  the  Caterham  Asylum,  having 
nearly  two  thousand  patients,  no  typhoid  fever  had  ap- 
peared, and  that  there  had  been  a  similar  absence  of  the 
disease  among  the  five  hundred  men  in  the  barracks. 
Both  these  establishments  derived  their  entire  water  from 
a  well  sunk  462  feet  into  the  chalk. 

In  the  meantime,  information  arrived  that  typhoid  fever 
was  also  epidemic  in  Red  Hill,  a  neighboring  community. 
Red  Hill  had  an  estimated  population  of  9500,  and  included 
two  or  more  villages,  besides  an  asylum  for  idiots.  It  was 
about  eight  miles  distant  from  Caterham,  lay  on  a  different 
geological  formation,  and  was  well  sewered.  Nevertheless, 
in  regard  to  typhoid  fever,  the  two  places  were  remarkably 
similar.  In  both,  the  epidemic  began  at  about  the  same  time. 
The  first  two  cases  in  Red  Hill  occurred  on  January  20; 
three  more  on  the  2ist;  five  more  on  the  22d;  twelve  on 
the  23d,  and  at  the  end  of  the  first  fortnight,  namely,  by 
February  2,  the  total  number  of  houses  affected  was 
96,  and  the  number  of  patients  had  reached  132. 
There  was  nothing  which  threw  suspicion  upon  the 
sewers.  The  community  had  been  totally  free  from 


194     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

the  disease  for  at  least  eighteen  months,  and  there 
was  no  reason  to  suspect  the  milk  supply.  The  water 
supply,  on  the  other  hand,  was  derived  for  the  most 
part  from  the  waterworks  of  the  Caterham  Waterworks 
Company,  and  a  sanitary  official,  Mr.  Jacob,  independently 
of  Dr.  Thorne  and  the  local  officer  in  Caterham,  had 
arrived  at  the  conclusion  that  the  Caterham  water  was  in  all 
probability  the  vehicle  of  the  disease.  Of  the  ninety-six 
houses  affected  during  the  first  fortnight  of  the  epidemic  at 
Red  Hill,  ninety-one  actually  drew  their  water  from  the 
Caterham  Company's  mains,  and  the  histories  obtained  with 
reference  to  the  attacks  in  the  remaining  five  cases  were  such 
as  to  confirm  the  impression  that  the  Caterham  Company's 
water  had  been  the  immediate  cause  of  the  epidemic. 
For  example,  at  one  of  these  houses  where  ultimately  three 
persons  were  attacked,  the  supply,  as  was  hitherto  believed, 
had  been  exclusively  derived  from  a  rain  water  tank,  but 
it  was  now  ascertained  that  the  Caterham  Company's  water 
was  in  addition  procured  surreptitiously;  that  at  another 
house,  for  which  there  was  apparently  no  water  supply,  the 
company's  water  was  procured  from  a  neighbor's;  and  with 
regard  to  the  remainder,  the  patients  infected  were  not 
only  persons  who  were  employed  where  the  company's 
water  was  in  use,  but  several  of  them  had  partaken  of  the 
water  at  their  meals. 

Certain  localities  in  Red  Hill,  namely,  Meadvale,  having 
about  160  houses,  and  in  Red  Hill  itself  a  group 
of  30  houses  supplied  with  wells,  were  practically 
exempt  from  typhoid  fever.  Still  more  striking  was  the 
case  in  Reigate,  a  town  which  forms  the  western  ward  of 
the  burough  of  which  Red  Hill  is  the  eastern  ward.  Rei- 
gate had  a  population  of  about  8500,  provided,  however, 
with  a  different  water  supply;  and  this  region  escaped 
entirely,  only  two  cases,  undoubtedly  imported  from  Red 
Hill,  having  occurred  there. 

All  the  facts  ascertained  in  connection  with  the  course 


TYPHOID  FEVER   IN   RED   HILL,  ENGLAND        195 

of  the  epidemic  up  to  February  2  afforded  very  strong 
presumption  that  it  had  been  caused  by  the  use  of  the 
Caterham  Company's  water.  Further  developments  made 
this  view  almost  certain. 

The  Waterworks  Company  derived  its  supply  from 
two  deep  wells,  situated  about  30  feet  apart,  and  about 
490  feet  deep.  Both  were  several  feet  in  diameter. 
Moreover,  they  were  connected,  by  three  adits  in  the 
chalk.  From  the  wells  the  water  was  pumped  to  reser- 
voirs, in  which  it  was  submitted  to  Clark's  softening 
process.  The  reservoirs  freely  communicated,  and  from 
them  the  supply  was  delivered  by  gravitation.  During 
the  preceding  twelve  months  a  third  well  had  been  made, 
90  feet  away  from  the  others  and  of  similar  depth. 
From  1861,  and  until  the  construction  of  the  third  boring, 
the  water  supplied  by  the  company  was  held  in  high 
repute ;  but  since  that  time,  and  prior  to  the  epidemic, 
complaints  had  been  made  with  regard  to  the  water. 
These  were  due  to  an  unavoidable  turbidity  and  to  inter- 
ruptions in  the  process  of  softening.  Apart  from  this 
turbidity  and  temporary  hardness,  there  was  no  reason 
to  believe  that  the  water  was  objectionable;  and  consider- 
ing the  deep  sources  of  the  supply,  it  was  by  no  means 
apparent  how  the  water  could  have  been  the  means  of  pro- 
ducing an  extensive  epidemic  of  typhoid  fever.  Dr.  Thorne 
inquired  carefully  into  the  possibility  of  contamination  of 
the  supply  en  route,  but  with  negative  results.  He  next 
sought  to  discover  whether  any  contamination  had  taken 
place  in  the  reservoirs  or  in  the  mains.  But  these  sources 
also  were  satisfactorily  excluded.  Many  other  points  re- 
lating to  the  method  of  distribution  of  the  water  were 
inquired  into,  but  none  led  to  any  explanation  of  the  cir- 
cumstances of  the  epidemic. 

It  was  next  suggested  that  cesspool  drainage  or  soakage 
of  surface  filth  might  have  existed  around  the  com- 
pany's wells.  Certain  cesspools  were  found  in  the  vicinity, 


196     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

but  after  careful  examination  were  excluded  as  probable 
sources  of  contamination. 

In  the  meantime  facts  were  brought  to  light  which  led  to 
an  extension  of  the  inquiry  in  another  direction.  It  ap- 
peared that  during  the  latter  part  of  1878  and  the  begin- 
ning of  1879,  the  company  had  constructed  an  adit  from 
one  of  their  old  wells  up  to  the  new  boring,  which  was  then 
being  sunk.  This  adit  was  in  the  chalk  at  a  depth  of 
445  feet.  It  was  6  feet  by  4  feet  in  section  and  90  feet 
long.  A  number  of  men  were  employed  in  the  work,  some 
of  them  being  in  the  wells  below,  others  on  the  surface. 
It  was  ascertained  that  one  of  the  men  who  left  work  some 
time  in  January  was  reputed  to  have  been  ill,  though  no 
inquiries  had  been  made  concerning  him  since  he  quitted 
the  works.  This  man  was  sought  out,  and  eventually  the 
following  facts  were  obtained :  — 

"  J.  K.,  aged  thirty-two  years,  resided  in  Caterham,  and  was  employed 
by  the  company  as  a  laborer  from  October  25, 1878.  The  work  assigned 
to  him  was  that  of '  loading-man,'  he  being  employed  in  the  adit  below 
in  attaching  to  a  rope  let  down  from  above  the  buckets  by  which  the 
excavated  chalk  was  raised  to  the  surface,  and  in  again  receiving  those 
buckets  when  lowered  full  of  bricks  and  cement  required  for  the  work 
in  progress.  From  December  14  to  December  29,  J.  K.  was  absent. 
When  he  returned  he  was  in  perfect  health,  but  in  about  a  week,  that  is, 
about  January  5,  1879,  he  felt  himself  ailing.  His  symptoms,  which, 
according  to  his  statement,  steadily  increased,  were  at  first  loss  of  appe- 
tite, recurring  attacks  of  shivering  alternating  with  a  feeling  of  heat, 
great  pains  in  the  limbs  which  he  attributed  to  rheumatism,  but  which, 
instead  of  being  confined  to  any  of  the  joints,  were  described  both  by 
himself  and  by  his  wife  as  an  '  aching  all  over,'  and  diarrhoea.  As  the 
symptoms  became  aggravated,  he  was  so  exhausted  during  his  work  and 
became  so  'giddified'  that  he  was  more  than  once  drawn  to  the  sur- 
face, and  immediately  on  his  return  home  he  was  compelled  to  go  to 
bed.  More  than  once  his  wife  noticed  that  he  was  '  light-headed '  in 
his  sleep.  All  this  while  the  diarrhoea  continued,  the  man  making  a 
great  effort  to  remain  at  his  work,  because,  as  explained,  he  had  had  no 
employment  between  the  i4th  and  the  zgth  of  the  previous  month. 

"  With  reference  to  this  man's  diarrhoea,  it  is  necessary  to  make  the 
following  explanation  :  Both  from  his  own  statement,  and  from  that  of 


TYPHOID  FEVER  IN   CATERHAM   AND   RED   HILL     197 

others,  it  appears  that  all  the  men  who  worked  in  the  adit  were  ex- 
pected to  make  such  preparation  before  descending  the  well  that  no 
occasion  should  exist  for  relieving  themselves  below  ;  but  should  such 
necessity  ever  arise,  and  should  there  be  at  such  a  time  any  difficulty  or 
delay  in  their  being  drawn  to  the  surface,  the  buckets  which  were  regu- 
larly being  raised  to  the  surface  were  to  be  used  for  that  purpose.  J. 
K.  states  that  he  strictly  complied  with  these  regulations  before  de- 
scending, but  that,  notwithstanding  all  his  efforts,  the  purging  under 
which  he  was  laboring  was  such  that  he  was  compelled  to  evacuate 
whilst  in  the  adit  '  at  least  two  or  three  times '  during  each  shift,  the 
shifts  lasting  apparently  from  eight  to  twelve  hours  each,  according  to 
circumstances.  Indeed,  as  time  went  on,  the  man's  diarrhoea  must 
have  been  considerable,  for  besides  the  attacks  which  came  on  whilst 
in  the  adit,  he  almost  invariably  suffered  from  it  before  descending,  im- 
mediately after  ascending,  and  also  at  his  own  house.  So  matters  con- 
tinued until  January  20,  when  work  was  again  suspended  for  two  days 
on  account  of  a  rise  in  the  water  level.  But  during  the  night  of  the 
2 1st  he  was  so  much  worse  that  he  was  unable  to  rise  next  morning. 
According  to  his  wife's  statement,  he  found  he  could  not  stand  when  he 
got  up,  and  returning  to  his  bed,  suffered  from  'shivering  down  the 
back,  aching,  and  exhaustion ' ;  and  later  on  severe  abdominal  pain 
came  on  which  compelled  him  to  lie  with  his  knees  drawn  up  ;  he  was 
also  '  burning  hot.'  This  pain  was  looked  upon  as  '  cramp,'  and  was 
alleviated  by  linseed-meal  poultices,  which  were  applied  by  his  wife. 
The  more  severe  symptoms,  including  the  diarrhoea,  having  subsided, 
he  was  two  days  afterward  able  to  get  up  for  a  while,  and  from  this 
time  convalescence  appears  to  have  set  in.  No  medical  advice  was 
sought,  mainly,  as  he  explained  to  me,  owing  to  his  straitened  circum- 
stances. When  I  saw  him,  on  February  the  8th,  he  had  the  aspect  of  a 
man  who  had  recently  suffered  from  some  acute  disease  ;  he  was  still 
very  weak,  and  it  was  obvious  that  he  had  greatly  lost  flesh." 

Dr.  Thorne  and  Dr.  Jacob  with  extreme  care  searched 
further  into  the  history  of  this  case,  with  the  following 
result,  in  Dr.  Thome's  words  :  — 

"  I  have  now  no  hesitation  in  taking  it  as  a  fact,  that  a  man  ill  of 
enteric  [typhoid]  fever  from  January  5  to  the  end  of  the  month  was 
occupied  during  the  first  fortnight  of  that  period  at  work  in  the  well  of 
the  Caterham  Waterworks  Company.  The  fact,  it  will  be  observed,  is 
not  inferred  from  any  consequences  of  it,  but  simply  from  what  was 
seen  and  heard  of  the  particular  individual. 

"  But  now  let  us  see  what  those  consequences  would  have  been.     If 


198     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

this  man's  stools  could  by  any  means  have  found  their  way  into  the 
water  of  the  well  in  which  he  had  been  working,  and  being  enteric 
fever  stools  could  thus  have  led  to  the  development  of  the  poison  of 
that  disease  in  the  well,  the  effect  on  the  water  consumers  ought  to 
have  been  noticed  within  from  about  ten  to  fifteen  days  after  the  date 
when  the  diarrhoea  first  came  on.  And  this,  in  effect,  is  precisely  what 
did  take  place,  the  epidemic  having  commenced  on  January  19  and  20 
in  Caterham  and  Red  Hill,  respectively.  This  remarkable  concurrence 
of  dates  led  to  a  more  detailed  inquiry  as  to  the  course  of  the  man's 
diarrhoea  whilst  working  in  the  adit.  He  admitted  that  the  purging 
was  very  copious,  in  short,  that  it  'ran  from'  him  ;  indeed,  when  at 
home,  he  was,  because  of  the  suddenness  of  its  onset,  unable  to  resort 
to  the  closet.  He  further  admitted  that,  owing  to  his  frequent  use  of 
the  bucket  whilst  at  work,  complaints  were  made  by  his  fellow-workmen 
on  the  surface  ;  but  he  stoutly  denied  that  he  had  ever  been  so  pressed 
by  necessity,  or  so  influenced  by  those  complaints,  as  to  relieve  himself 
in  the  adit  without  waiting  for  a  bucket.  But  even  accepting  his  de- 
nial, there  were  undoubted  means  by  which  his  evacuations  could  have 
found  their  way  into  the  water.  According  to  his  statement,  the  bucket 
was  used  as  a  closet  when  it  was  empty,  when  half  full,  and  when  full  ; 
he  added,  however,  that  when  it  was  full  he  first  took  some  of  the  chalk 
out  and  subsequently  replaced  it.  During  an  earlier  stage  of  my  in- 
quiry- I  had  occasion  to  descend  one  of  these  wells,  and  I  noticed  that 
any  article  let  down  by  a  rope,  by  its  oscillations  to  and  fro,  came  into 
constant  and  somewhat  violent  contact  with  the  walls  of  the  wells,  and 
on  inquiry  of  J.  K.  whether  the  same  did  not  take  place  with  the  bucket, 
he  admitted  not  only  that  this  was  so,  but  that  some  of  its  contents  fre- 
quently fell  over  a  stage  into  the  water  below.  On  further  inquiry,  he 
added  that  some  portions  of  his  evacuations  probably  did  so  also.  And 
he  further  stated  that  the  looseness  of  his  bowels  was  such  that  the 
bucket  itself  must  almost  of  necessity  have  been  stained  with  them. 
This  bucket,  which  was  merely  emptied  out  above,  then  received,  as 
already  explained,  materials  which  were  used  in  the  construction  of  the 
works  below.  Here,  then,  were  the  stools  of  an  enteric  fever  patient, 
from  about  January  5  onwards,  getting  into  the  Caterham  Company's 
water  and  distributed  with  that  water  to  the  district  served  by  the 
company. 

"  Now  we  know  from  ample  experience  that  enteric  fever  is  produced, 
and  produced  with  the  maximum  of  certainty,  when  the  specific  evacua- 
tions of  that  disease  are  consumed  by  a  population.  Again,  it  is  a  mat- 
ter of  experience  that  where  enteric  fever  has  been  conveyed  through 
water,  some  fortnight  has  to  elapse  between  the  distribution  of  the 
water  and  the  occurrence  of  the  disease  among  the  community  served 


TYPHOID  FEVER  IN  CATERHAM   AND   RED   HILL     199 

by  it.  But  a  fortnight  after  January  5  to  19,  i.e.  from  January  19  to 
February  2,  the  disease  became  widely  spread  throughout  Caterham 
and  Red  Hill  ;  the  distribution  of  the  fever  being  limited,  as  we  have 
already  seen,  to  houses  supplied  with  the  water  of  the  Caterham  Com- 
pany. There  can,  I  think,  be  no  doubt  that  we  have  in  the  man  J.  K. 
the  cause  of  the  disease  which  followed." 

A  further  study  by  Dr.  Thorne  made  with  similar  care 
showed  that  wherever  the  Caterham  water  indubitably  went, 
typhoid  fever  was  also  distributed.  A  part  of  this  latter 
investigation  was  particularly  interesting.  The  village  of 
Warlingham,  lying  about  three  miles  from  the  Caterham 
Company's  Works,  was  supplied  by  that  company  with 
water,  and  yet  had  no  typhoid  fever.  It  appeared  in  the 
sequel,  however,  that  in  order  to  add  to  the  Caterham 
Company's  supply  during  certain  portions  of  the  time 
when  the  Caterham  wells  were  undergoing  alterations  and 
furnishing  a  diminished  supply,  water  had  been  pumped 
into  the  Caterham  Company's  mains  by  the  Kenley  Water- 
works Company;  namely,  continuously  every  night  after 
November  26,  1878,  to  January  3,  1879;  resumed  again 
from  January  5  to  10,  then  discontinued  until  the  nights  of 
the  I4th  and  iSth,  finally  ceasing  on  the  morning  of  the 
1 6th.  This  water  was  therefore  pumped  into  the  Caterham 
Company's  mains  for  the  period  January  5  to  9,  during 
which  the  distribution  of  infection  must  have  commenced. 
The  Kenley  water  was  not,  however,  mixed  directly  with 
the  Caterham  water.  It  was  pumped  in  at  one  particular 
point,  and  that  point  was  the  extreme  farther  end  of  the 
Warlingham  branch  of  the  system.  Furthermore,  the  ca- 
pacity of  the  main  between  Caterham  and  Warlingham,  and 
of  the  branches  of  this  main  in  Warlingham,  was  somewhat 
over  12,000  gallons.  Accordingly,  before  the  Kenley  water 
could  get  to  the  Caterham  Company's  reservoirs,  it  had  to 
fill  the  whole  of  the  three-inch  Warlingham  main  and  its 
system  of  branches,  besides  one  other  larger  main  nearer  to 
Caterham.  It  is  therefore  fair  to  suppose  that  the  inhab- 


200    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

itanfs  of  Warlingham  rarely,  if  at  all,  and  probably  never, 
during  this  time,  received  any  of  the  Caterham  water.  In 
the  end  Dr.  Thorne  was  led  to  believe  that  the  almost  com- 
plete exemption  of  Warlingham  —  for  only  a  single  case 
appeared  there  during  the  epidemic  period  —  was  powerful 
support  to  his  views  in  regard  to  the  true  source  of  this 
epidemic. 

The  total  number  of  cases  was  352,  and  the  total  number 
of  deaths,  21,  to  the  end  of  February.  After  that  time 
only  a  few  scattered  cases  occurred.  The  disease,  as  has 
been  stated,  was  typical  typhoid  fever,  the  patients  exhibit- 
ing the  characteristic  rose-spots,  diarrhoea,  etc.  Most  of 
the  cases  were  of  an  exceptionally  mild  character,  and  the 
majority  attacked  were  children.  Amongst  adults,  women 
were  more  frequently  attacked  than  men.  The  low  fatality 
is  noteworthy,  and  agrees  with  the  theory  of  great  dilution 
of  the  infectious  material. 

§  8.  —  An  Epidemic  of  Typhoid  Fever  in  Plymouth  (Penn- 
sylvania) traced  to  a  Polluted  Surface  Water  Supply 

One  of  the  most  instructive  epidemics  in  the  annals  of 
sanitary  science  is  the  epidemic  of  typhoid  fever  which 
sprang  from  a  polluted  water  supply  in  Plymouth,  Penn., 
in  the  spring  of  1885.  Plymouth  at  that  time  was  a  mining 
town  of  about  eight  thousand  inhabitants.  It  had  grown  up 
rapidly,  and  was  not  in  good  sanitary  condition ;  but  it  was 
provided  with  an  apparently  excellent,  though  limited,  pub- 
lic water  supply  derived  from  a  mountain  stream,  travers- 
ing an  almost  uninhabited  watershed.  There  were,  in  fact, 
on  the  watershed  only  two  houses  so  placed  as  to  be  able 
to  contaminate  the  supply.  It  would  appear  from  the  ex- 
cellent report  of  Dr.  L.  H.  Taylor,1  of  Wilkesbarre,  from 
which  the  present  account  is  drawn,  that  the  inhabitants 

1  First  Annual  Report,  State  Board  of  Health  and  Vital  Statistics  of  Penn- 
sylvania, pp.  176-195.  Harrisburg,  Penn.,  1886. 


TYPHOID  FEVER  IN  PLYMOUTH,   PENN.  2OI 

of  one  or  both  of  these  had  nevertheless  for  some  time, 
perhaps  for  years,  been  polluting  the  public  supply  of 
Plymouth  with  ordinary  faecal  matters;  but  no  harm  was 
observed  or  even  suspected  until  April,  1885,  when,  as  was 
afterward  discovered,  the  specific  infection  of  typhoid  fever 
was  superadded  to  ordinary  faecal  pollution.  Thereupon, 
out  of  a  population  of  about  8000  persons,  1104  con- 
tracted typhoid  fever,  and  114  died.  The  story  may  be 
briefly  told. 

"  The  first  case  belonging  to  this  epidemic  occurred  on  April  9,  and 
from  this  time  on  the  disease  spread  rapidly.  During  the  week  begin- 
ning April  12,  from  fifty  to  one  hundred  new  cases  appeared  daily, 
and  on  one  day  it  is  said  two  hundred  new  cases  were  reported.  .  .  . 
Various  theories  were  put  forth,  some  declaring  it  [the  epidemic]  to  be 
due  to  the  filth  of  the  town ;  some  that  it  was  due  to  drinking  polluted 
well  water ;  others,  polluted  river  water ;  and  still  others  that  it  was  due 
to  a  peculiar  condition  of  nature,  by  no  means  explainable. 

"  Among  the  various  theories  advanced,  one  of  the  first  was  that  it  was 
due  to  the  accumulated  filth  of  the  town,  which,  being  acted  upon  by 
the  warm  rays  of  the  April  sun,  had  suddenly  become  noxious,  and  the 
emanations,  therefore,  had  caused  the  disease.  This  especially  suited 
the  '  typho-malarial '  theorists.  But  although  Plymouth  was  not  an  espe- 
cially clean  town,  it  was  not,  on  the  other  hand,  more  filthy  than  other , 
neighboring  towns  where  the  disease  did  not  prevail,  nor  was  it  at  this 
particular  time  in  worse  condition  than  in  preceding  years.  .  .  . 

"  All  classes  of  people  were  attacked,  the  clean  as  well  as  the  filthy, 
and  all  parts  of  the  town  affected,  the  highlands  as  well  as  the  valley 
.  .  .  and  thoughtful  minds  naturally  turned  to  the  water  supply  as  fur- 
nishing the  true  cause  of  the  invasion." 

In  addition  to  certain  wells  and  springs  the  inhabitants 
had  access  to  one  or  both  of  two  public  water  supplies.  A 
small  portion  of  the  town  received  regularly  water  from  the 
Susquehanna  River,  pumped  by  the  Delaware  and  Hudson 
Coal  Company,  and  those  who  used  this  water  exclusively 
did  not  suffer  from  the  disease.  The  greater  portion,  how- 
ever, was  supplied  by  the  Plymouth  Water  Company, 
which  in  1876  began  supplying  the  town  "with  water  of 
remarkable  purity,  from  a  neighboring  mountain  stream 


202     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

which  had  its  source  in  a  beautiful  sand  spring  some  miles 
away."  On  the  stream  had  been  built,  successively,  four 
storage  reservoirs:  No.  I,  the  first,  the  lowest,  and  that  serv- 
ing as  the  distributing  reservoir  (see  diagram),  having  a 
capacity  of  300,000  gallons ;  No.  2,  next  above,  a  capacity 
of  1,700,000  gallons;  No.  3,  still  higher,  of  3,000,000  gal- 
lons ;  and  finally,  No.  4,  highest  of  all,  of  5,000,000  gallons. 
In  spite  of  this  storage  capacity,  however,  the  supply  was 
at  times  insufficient,  and  was  then  supplemented  by  direct 
pumping  from  the  Susquehanna  River,  a  stream  polluted, 
and  at  times  infected,  by  the  sewage  of  Wilkesbarre,  a  city 
of  30,000  inhabitants,  lying  on  the  same  river  only  three 
miles  above.  "  Water  from  the  river  was  first  pumped  .  .  . 
in  1878,  and  occasionally  in  succeeding  years,  e.g.  in  1881, 
91  days;  in  1882-1883,  ...  65  days;  1883-1884,  124 
days;  1884  [additional],  118  days.  This  water,  though 
objectionable,  .  .  .  has  never  been  followed  by  any  [re- 
ported] epidemic  of  typhoid  fever." 

In  the  spring  of  1885  resort  was  again  had  to  the  river, 
which  was  used  just  before  the  epidemic  appeared,  viz. 
from  March  20  to  26,  1885.  Dr.  Taylor  was  therefore 
obliged  to  consider  very  carefully  the  possibility  that  the 
source  of  the  epidemic  lay  in  the  river  water.  He  was  able, 
nevertheless,  by  various  independent  lines  of  evidence,  to 
show  conclusively  that  the  great  epidemic,  which  began 
with  a  single  case  on  April  9,  and  by  the  end  of  another 
week  had  risen  to  alarming  proportions,  could  not  possibly 
be  attributed  to  the  use  of  the  sewage-polluted  river  water. 
It  was  easy  to  show  that  the  milk  supply  and  the  well- 
water  and  spring-water  supplies  could  not  furnish  adequate 
explanation  of  the  epidemic,  so  that  there  remained  only 
the  mountain  supply  of  water  to  be  investigated. 

"  There  remains  but  one  possible  cause  for  this  most  serious  and  de- 
plorable outbreak,  and  that  is  contamination  of  the  water  supplying  the 
company's  reservoirs.  A  glance  at  the  accompanying  map  will  show 
the  location  of  this  stream  and  of  the  several  reservoirs.  Above  the 


4T5  RESERVOIR 


HOUSE  FROM  WHICH 
INFECTION  CAME . 


MAP  OF 

PLYMOUTH,  PENN, 

IN      1885. 


H« 


1O   MAM 

.HTUOMYJ^ 


TYPHOID   FEVER   I>N   PLYMOUTH,   PENN.          203 

starting  point  of  the  water  pipes  there  is  but  one  house  situated  upon 
the  banks  of  this  stream,  and  one  upon  the  banks  of  the  fourth 
reservoir. 

"  In  the  house  between  the  third  and  fourth  reservoirs,  situated 
almost  immediately  upon  the  stream,  there  lives  a  man  who  but  recently 
has  recovered  from  the  effects  of  a  severe  attack  of  typhoid  fever.  This 
patient  went  to  Philadelphia,  December  24,  1884,  and  while  there,  he 
thinks,  contracted  the  disease.  Whether  he  did  thus  contract  the  dis- 
ease in  Philadelphia  may,  we  think,  admit  of  question.  But  it  is  never- 
theless true  that  he  returned  to  his  home,  January  2, 1885,  and  for  many 
weeks  was  seriously  ill  with  genuine  typhoid  fever.  Early  in  March  he 
was  convalescent  and  was  out  of  bed.  A  relapse  occurred  about  the 
middle  of  March,  and  he  was  very  sick  on  the  i6th.  On  March  16  and 
17  he  had  hemorrhages  of  the  bowels  of  so  severe  a  type  that,  on  March 
1 8,  his  life  was  despaired  of,  even  by  his  physician. 

"  He,  however,  rallied,  was  quite  ill  for  some  time,  but  was  con- 
valescent in  April,  so  that  his  physician  discontinued  his  visits  after 
April  12. 

"  During  the  course  of  his  illness,  his  dejecta  passed  at  night,  with- 
out any  attempt  at  disinfection,  were  thrown  out  upon  the  snow  and 
frozen  ground,  toward  and  within  a  few  feet  of  the  edge  of  the  high 
bank,  which  slopes  precipitously  down  to  the  stream  supplying  the  town 
with  water. 

"  The  nurse  in  charge  states  explicitly  that  in  emptying  the  chambers 
at  night  she  did  not  stand  on  the  porch  to  throw  out  the  contents,  but 
stepped  down  some  distance  and  threw  them  into  the  creek.  If  she 
stepped  but  a  few  feet  away  from  the  porch,  she  would  empty  the  ex- 
creta within  twenty-five  or  thirty  feet  of  the  edge  of  the  stream. 

"  The  dejecta  passed  during  the  day  were  emptied  into  a  privy  a  little 
farther  back,  the  contents  of  which  lie  almost  upon  the  surface  of  the 
ground,  and  at  the  first  thaw  or  rain  they  too  would  pass  down  the  slop- 
ing bank  and  into  the  stream.  These  dejecta  were  thrown  out  from 
time  to  time  until  the  accumulation  no  doubt  equalled  the  daily  passages 
from  many  such  patients.  They  remained  innoxious  upon  the  snow  and 
frozen  ground  until  some  time  between  March  25  and  April  I,  when  they 
were  washed  into  the  stream  and  thence  into  the  third  reservoir. 

"  The  house  in  question  does  not  stand  in  a  ravine  nor  in  a  pro- 
tected spot,  but  in  an  open  clearing,  with  land  sloping  toward  the  south, 
which  clearing  would  naturally  feel  the  effects  of  the  sun's  rays  and  part 
with  its  snow  and  accumulated  filth  sooner  than  the  more  protected  re- 
gions which  also  drain  into  the  stream,  so  without  cavil  the  first  water 
from  the  effects  of  the  thaw  to  enter  the  third  reservoir  would  be  from 
the  melted  snow  in  the  immediate  vicinity  of  this  house. 


I 
204    WATER  AS  A  VEHICLE  <  F  INFECTIOUS  DISEASE 

"The  maximum  temperature  .  .  .  was  on  March  26, 46.5°  F. ;  March 
27,  56° ;  March  28,  43° ;  March  29,  37°,  increasing  rapidly  until  April  4, 
when  a  temperature  of  70°  F.  was  reached. 

"March  26,  with  a  maximum  temperature  of  46.5°  F.,  is  the  first  day 
on  which  any  considerable  thaw  could  occur.  Upon  the  evening  of  this 
day,  the  superintendent  of  the  water  company  visited  the  reservoirs  to 
ascertain  whether  it  would  be  allowable  to  discontinue  the  pumping  of 
river  water.  He  found  the  first  and  second  reservoirs  almost  entirely 
empty,  while  the  third  was  filling  rapidly,  the  short  pipe  which  allows 
the  water  to  discharge  from  the  bottom  of  the  third  into  the  stream  lead- 
ing to  the  second  reservoir  being  tightly  frozen. 

"  He  caused  a  fire  to  be  built  to  melt  the  ice  in  this  pipe,  and  then 
stopped  the  river  pumps.  The  honest  act  of  an  honest  man,  and  sim- 
ply in  the  discharge  of  his  duty  and  with  kindliest  intent.  But  of  what 
a  catastrophe  was  he  the  unconscious  usher  and  hastener  !  The  water, 
with  its  accumulated  typhoid  fever  poison,  was  discharged  from  the  bot- 
tom of  the  third  reservoir,  ran  down  to  the  second,  on  to  the  first,  and 
was  thence  distributed  to  the  town,  in  all  probability  between  the  28th 
of  March  and  the  4th  or  5th  of  April. 

"In  considering  the  possibility  of  one  patient  poisoning  more  than  a 
thousand  in  Plymouth,  we  must  bear  in  mind  all  the  attending  cir- 
cumstances :  — 

"  I .  The  accumulation  of  weeks  —  which  equalled  the  dejecta  from 
many  ordinary  patients,  and  which  lay  for  a  time  dormant  upon  the 
snow  and  frozen  ground. 

"  2.  The  nearness  to  the  stream.  The  house  is  so  situated  that  all 
of  the  excreta  were  thrown  within  a  few  yards  of  its  banks,  and  the  con- 
formation of  the  ground  is  such  that  its  surface  water  could  not  possibly 
drain  in  any  other  direction. 

"  3.  The  unusually  warm  weather  —  which  caused  a  sudden  thaw  and 
poured  the  surface  water  into  the  empty  reservoir. 

"  4.   The  concentration  of  the  poison  in  a  small  amount  of  water. 

"  5.  The  short  distance  to  the  town ;  and  finally,  the  possible  previous 
preparation  of  the  soil  for  the  reception  of  this  seed,  which  sprang  at 
once  into  vigorous  growth  and  ripened  for  an  abundant  harvest  of 
death. 

"  It  would  seem  that  the  mere  statement  of  facts,  as  found  in  the  few 
preceding  pages,  is  amply  sufficient  to  explain  the  cause  of  this  remark- 
able epidemic,  and  we  need  have  no  hesitation  in  declaring  the  pollution 
of  the  mountain  stream,  which  supplies  the  reservoirs  of  the  water  com- 
pany of  Plymouth,  to  be  the  sole  cause  of  the  remarkable  outbreak  of 
typhoid  fever  in  this  borough. 


TYPHOID   FEVER   IN   PLYMOUTH,   PENN.          205 

"  During  the  period  of  pumping  from  the  Susquehanna,  the  water  in 
that  river  was  lower  than  it  had  been  at  any  time  for  years,  and  the 
surface  was  frozen  tight.  The  city  of  Wilkesbarre,  containing  thirty 
thousand  inhabitants,  delivers  its  sewage  directly  into  the  Susquehanna, 
the  mouth  of  the  lower  sewer  emptying  only  two  miles  above  the  Ply- 
mouth Pumping  Station,  while  the  current  is  very  rapid  between  the 
two  towns.  The  water  is  further  contaminated  by  refuse  water  from 
five  or  six  lines  as  well  as  by  the  garbage  from  the  abattoirs  at  Wilkes- 
barre. Notwithstanding  this  unusually  filthy  condition  of  the  Susque- 
hanna River,  it  is  beyond  question  entirely  innocent  of  causing  the 
epidemic.  .  .  ." 

Dr.  Taylor's  conclusions  were  confirmed  in  all  essential 
particulars  by  other  students  of  the  epidemic,  among  whom 
may  be  mentioned  Drs.  Shakespeare  and  French  of  Phila- 
delphia ;  Briggs  of  Buffalo  ;  and  Biggs,  Taylor,  Edson  and 
others,  of  New  York.  The  first  to  suggest  publicly  the 
pollution  of  the  mountain  supply  as  the  probable  cause  of 
the  epidemic  was  Dr.  R.  Davis  (in  a  Wilkesbarre  newspaper 
published  on  April  29). 

We  may  readily  agree  with  Dr.  Taylor  in  his  conclu- 
sions :  — 

"  It  is  safe  to  say  that  this  was  one  of  the  most  remarkable  epidemics 
in  the  history  of  typhoid  fever,  and  it  teaches  us  some  important  lessons, 
at  fearful  cost.  One  is,  that  in  any  case  of  typhoid  fever,  no  matter  how 
mild,  nor  how  far  removed  from  the  haunts  of  men,  the  greatest  possible 
care  should  be  exercised  in  thoroughly  disinfecting  the  poisonous  stools. 
The  origin  of  all  this  sorrow  and  desolation  occurred  miles  away,  on 
the  mountain  side,  far  removed  from  the  populous  town,  and  in  a  soli- 
tary house  situated  upon  the  bank  of  a  swift-running  stream.  The  at- 
tending physician  did  not  know  that  this  stream  supplied  the  reservoirs 
with  drinking  water.  Here,  if  any  place,  it  might  seem  excusable  to 
take  less  than  ordinary  precautions  ;  but  the  sequel  shows  that  in  every 
case  the  most  rigid  attention  to  detail  in  destroying  these  poisonous 
germs  should  be  enjoined  upon  nurses  and  others  in  charge  of  typhoid 
fever  patients,  while  the  history  of  this  epidemic  will  but  add  another  to 
the  list  of  such  histories  which  should  serve  to  impress  medical  men, 
at  least,  with  the  great  necessity  for  perfect  cleanliness  —  a  lesson  which 
mankind  at  large  is  slow  to  learn. 

"  Another  lesson  taught  by  this  history  comes  more  nearly  home  to 
us  all.  The  water-companies  throughout  our  land  should  be  taught 


206     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

that  they  must  furnish  us  the  water  for  which  we  pay,  from  the  very 
best  source  which  the  country  affords.  Not  only  should  they  avoid  the 
use  of  river  water  contaminated  by  sewage,  but  they  should  be  com- 
pelled to  remove  from  the  banks  of  their  streams  and  reservoirs  not 
only  all  probable,  but  all  possible  sources  of  pollution." 

Dr.  M.  S.  French  made  an  interesting  estimate  of  the 
financial  waste  or  loss  involved  in  the  Plymouth  epidemic, 
and  his  paper,  which  follows  that  of  Dr.  Taylor  (pp.  196- 
217,  /.  c.\  contains  also  a  complete  and  impressive  list  by 
name  of  those  attacked  with  typhoid  fever.  Dr.  French 
estimates  the  cost  of  the  sickness  —  "  expenses  incurred  by 
the  epidemic  "  —  at  $67,100.17,  of  which  $8,000  were  spent 
in  maintaining  a  temporary  hospital. 

"  Of  those  who  were  ill  with  the  disease  and  recovered, 
the  loss  of  earnings  during  their  illness  was  found  to  be 
$30,020.08.  Thus  the  total  cost  of  the  epidemic  is  reckoned 
at  $97,120.25.  By  the  114  deaths,  a  monthly  earning  of 
$1,534.96  ceased,  showing  a  loss  of  $18,419.52  per  year  in 
incomes." 

Dr.  French  does  not,  as  he  might  have  done,  capitalize 
this  latter  sum,  and  add  the  result  to  the  gross  loss ;  if  he 
had  done  so,  he  might  have  concluded  that  the  total  cost  of 
this  disastrous  epidemic  was  more  than  half  a  million  of 
dollars.  It  will  be  observed  that  the  fatality  (i  14  deaths  in 
1104  cases)  was  much  higher  than  in  the  Caterham  epi- 
demic (21  deaths  in  352  cases),  or  10.3  per  cent  against  5.9 
per  cent,  and  that  this  corresponds  well  with  the  probable 
relative  concentration  of  the  infectious  material  in  the  two 
epidemics. 


THE  COST   OF   AN   EPIDEMIC  207 

§  9.  —  Typhoid  Fever  in  Lowell,  Lawrence  and  Other 
Cities  on  the  Merrimac  River 

In  the  valley  of  the  Merrimac  River,  which  is  a  large, 
swift  stream  draining  a  considerable  portion  of  southern 
New  Hampshire  and  northern  Massachusetts,  are  situated 
a  number  of  cities  and  towns  of  which  the  history  in  re- 
spect to  typhoid  fever  is  interesting  and  instructive.  Situ- 
ated in  the  same  valley,  under  closely  similar  climatic 
conditions,  they  are  also,  for  the  most  part,  manufacturing 
towns  or  cities,  and  have  populations  especially  favorable 
for  purposes  of  sanitary  comparison.  Lowell,  Lawrence 
and  Manchester  are  devoted  chiefly  to  textile  industries, 
and  nearly  the  same  might  be  said  of  Nashua  and  Con- 
cord, while  Haverhill  is  what  is  called  a  "shoe"  town,  and 
Newburyport,  while  possessing  some  textile  industries,  is 
more  diversified  in  this  respect. 

In  connection  with  his  duties  as  biologist  to  the  State 
Board  of  Health  in  Massachusetts,  and  especially  with  his 
work  at  the  Lawrence  Experiment  Station  of  that  Board, 
the  author  was  already  somewhat  familiar  with  the  sanitary 
history  of  the  cities  and  towns  situated  in  the  Merrimac 
Valley,  when,  in  December,  1890,  a  serious  epidemic  of 
typhoid  fever  having  appeared  in  the  city  of  Lowell, 
lying  only  nine  miles  above  Lawrence,  he  was  instructed 
by  the  Board  to  make  a  thorough  investigation.  At 
almost  the  same  time  he  was  also  invited  by  the  Water 
Commissioners  of  Lowell  to  conduct  a  similar  inquiry  on 
their  behalf.  Accordingly,  clothed  with  ample  authority 
and  provided  with  every  opportunity,  he  set  to  work. 

The  population  and  death-rates  from  typhoid  fever  in 
the  principal  cities  of  the  Merrimac  for  the  two  years 
preceding  the  outbreak  of  the  great  epidemic  of  1890-1891 
are  shown  in  the  following  tables  :  — 


208     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 


TYPHOID   FEVER  IN  THE  PRINCIPAL  CITIES  ON  THE 
MERRIMAC   RIVER 

DEATHS  PER  100,000  INHABITANTS  (POPULATION  FROM  UNITED  STATES 
CENSUS  OF  1890) 

1888-1889 


• 

jl 

£ 

s 

X 

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O 

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S 
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£ 

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Concord,  N.  H  

.O 

.0 

.O 

.0 

5-9 

17.6 

17.6 

17.6 

11.8 

.0 

.0 

.0 

70.5 

Manchester,  N.  H.  .     .     . 

.0 

2-3 

4-6 

.0 

.0 

4-6 

.0 

6-9 

6-9 

2.3 

.0 

2.3 

29.9 

Nashua,  N.  H  

5-3 

.0 

.0 

.0 

.0 

15.9 

31.8 

5-3 

10.6 

.0 

.0 

.0 

68.9 

Lowell,  Mass  

10.4 

7-8 

3-9 

3-9 

3-9 

10.4 

6.5 

9.2 

9.2 

5-3 

6.6 

9.2 

86.3 

Lawrence,  Mass.     .    .    . 

II.  2 

9.0 

II.  2 

2.2 

9.0 

.0 

17.9 

13-4 

13-4 

4-4 

•  5-6 

17.9 

125.2 

Haverhill,  Mass.     .    .     . 

.O 

.0 

3-8 

.O 

3-8 

3-8 

3-8 

.0 

.0 

3-8 

3-8 

.0 

22.8 

1889-1890 


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5-9 

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5-9 

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n.8 

.0 

.0 

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.0 

.0 

«).5 

Manchester,  N.  H.     .     . 

a-3 

.0 

2-3 

2.3 

7.0 

4-7 

4-7 

9-3 

4-7 

4'5 

.0 

.0 

41.8 

Nashua,  N.  H  

.0 

.0 

.0 

.0 

.0 

.0 

S-3 

10.7 

5-3 

5-3 

10.6 

5-3 

4»  5 

Lowell,  Mass  

9.2 

6.6 

4-0 

x-3 

6.6 

9.2 

4.0 

11.9 

11.9 

6.4 

7-7 

5.1 

83.9 

Lawrence,  Mass.     .    .    . 

8.9 

8-9 

II.  2 

4'4 

6-7 

15.6 

8-9 

6-7 

13-4 

15.6 

'3-4 

4-4 

118.1 

Haverhill,  Mass.     .     .    . 

3-8 

.O 

.O 

3-8 

3-8 

.0 

7-5 

.O 

3-8 

3-8 

3-8 

.0 

30.3 

Newburyport,  Mass.   .     . 

28  8 

TYPHOID   FEVER   IN   THE   MERRIMAC  VALLEY       209 


The  death-rates  for  the  epidemic  years  1890-1891  are 
shown  in  the  following  table  :  — 

TYPHOID  FEVER  IN  THE  PRINCIPAL  CITIES  ON  THE 
MERRIMAC   RIVER 

DEATHS  PER  100,000  INHABITANTS  (POPULATION  FROM  UNITED  STATES 
CENSUS  OF  1890) 

189O-1891 


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5-9 

ii.  S 

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•  .0 

ii.  8 

17-6 

.0 

.0 

.0 

.0 

.0 

5-9 

53-o 

Manchester,  N.  H.      .     . 

.0 

2-3 

.0 

2.3 

4.6 

6.9 

.0 

6.9 

11.4 

4-6 

4-6 

.0 

43-6 

Nashua,  N.  H  

.0 

.0 

7  8 

10.4 

7  8 

7  ft 

18.1 

Haverhill,  Mass.     .     .    . 

7-5 

38 

.0 

7-5 

.0 

"•3 

.0 

3-8 

.0 

.0 

.0 

.0 

33-9 

Newburyport,  Mass.    .     . 

.0 

.0 

7.2 

.0 

.0 

14-4 

21.6 

.0 

7.2 

7.2 

.0 

.0 

57-6 

The  death-rates  for  the  same  cities  for  the  two  years 
next  after  the  great  epidemic  of  1890-1891  are  shown  in 
the  following  tables  :  — 

TYPHOID  FEVER  IN  THE  PRINCIPAL  CITIES  ON  THE 
MERRIMAC   RIVER 

DEATHS  PER  100,000  INHABITANTS  (POPULATION  FROM  UNITED  STATES 
CENSUS  OF  1890) 

1891-1893 


V 

I 

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jj 

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S-9 

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.O 

17-6 

.0 

5-9 

.0 

.0 

.0 

.0 

.0 

29-4 

Manchester,  N.  H.      .     . 

a-3 

.0 

2-3 

.0 

.O 

.0 

.0 

.0 

.0 

4-6 

.0 

*-3 

11.5 

Nashua,  N.  H  

.0 

.0 

.0 

.0 

15.8 

15.8 

10.6 

31-7 

5-3 

5-3 

5-3 

.0 

89.3 

Lowell,  Mass  

7.8 

5-a 

1.3 

5.2 

3-9 

3-9 

9.1 

3-9 

2.6 

1  6.8 

10.4 

n.6 

81.7 

Lawrence,  Mass.     .     .     . 

6.7 

4-5 

2.2 

2.2 

2.2 

II.2 

6.7 

9.0 

2.2 

II.  2 

15-6 

17.9 

91.6 

Haverhill,  Mass.     .     .     . 

7-5 

.0 

.O 

.O 

3.8 

.O 

.0 

3-8 

3.8 

7-5 

3.8 

.0 

30.2 

Newburyport,  Mass.    .     . 

.0 

7.2 

7-2 

.O 

.0 

.O 

7.2 

.0 

7-» 

,o 

.0 

.0 

28.3 

210     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

1892-1893 


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5-9 

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ii.  8 

Manchester,  N.  H.      .    . 

2-3 

.0 

4-6 

6.9 

.O 

2-3 

.0 

.0 

2-3 

2-3 

.O 

.0 

20.7 

Nashua,  N.  H  

.0 

.0 

.0 

.0 

.O 

5-3 

.0 

»5-9 

5-3 

.0 

5-3 

.0 

31-8 

Lowell,  Mass  

5-2 

9.1 

2.6 

5-2 

5-2 

9-1 

5-2 

3-9 

12.9 

12.9 

9-i 

5-2 

85.6 

Lawrence,  Mass.     .     .     . 

6.7 

2.2 

4-5 

9.0 

4-5 

.0 

6.7 

9.0 

20.  i 

6-7 

26.8 

17.9 

114.1 

Haverhill,  Mass.     .    .    . 

3-8 

.O 

3-8 

3-8 

.0 

7-5 

.0 

3-8 

22.5 

.0 

15.0 

3-8 

64.0 

Newburyport,  Mass.    .     . 

.0 

14.4 

.0 

.0 

.O 

7-2 

71  6 

.0 

7.2 

50.4 

The  death-rates  from  typhoid  fever  for  twelve-month 
periods  in  the  principal  cities  on  the  Merrimac  River, 
for  five  years  in  succession,  are  shown  on  the  following 
table:  — 

DEATH-RATES  FROM  TYPHOID  FEVER,  BY  PERIODS  OF 
TWELVE  MONTHS,  IN  THE  PRINCIPAL  CITIES  ON  THE 
MERRIMAC  RIVER,  FOR  THE  FIVE  YEARS,  APRIL  I,  1888, 
TO  MARCH  31,  1893. 

DEATHS  PER  100,000  INHABITANTS  (POPULATION  FROM  UNITED  STATES 
CENSUS  OF  1890) 


From 

From 

From 

From 

From 

Average 

Apr.,  1  888, 

Apr.,  1  889, 

Apr.,  1890, 

Apr.,  1891, 

Apr.,  1892, 

Apr.,  1888, 

to 

to 

to 

to 

to 

to 

Mar.,  1889 

Mar.,  1890 

Mar.,  1891 

Mar.,  1892 

Mar.,  1893 

Mar.,  1893 

Concord,  N.  H.  .    .    . 

7°-5 

29-5 

53-° 

29.4 

n.8 

38.8 

Manchester,  N.  H.  .     . 

29.9 

41.8 

43-6 

11.5 

20.7 

39.5 

Nashua,  N.  H.    .    .    . 

68.9 

42-5 

5-3 

89.8 

31-8 

477 

Lowell,  Mass.      .     .     . 

86.3 

83.9 

'95-4 

81.7 

85.6 

10661  l 

Lawrence,  Mass.     .     . 

125.2 

nS.i 

187.0 

91.6 

114.1 

127.  a.  * 

Haverhill,  Mass.      .     . 

22.8 

30.3 

33-9 

30.8 

64.0 

463 

Newburyport,  Mass. 

144 

28.8 

57-6 

28.8 

5°-4 

36.0 

A  very  brief  consideration  of  the  facts  laid  down  in  this 
table  reveals  certain  striking  phenomena.  In  the  first 
place,  it  is  evident  that  none  of  these  cities  was  free  from 

1  Excluding  1890-1891  (the  period  of  the  great  epidemic),  the  average  for  the  other  four 
years  is  84.4  for  Lowell,  and  for  Lawrence,  112.25. 


TYPHOID   FEVER   IN   LOWELL  AND   LAWRENCE     211 

typhoid  fever,  at  least  for  any  considerable  length  of  time. 
In  the  second  place,  on  the  whole  (as  seen  from  the  last 
column  of  the  last  table),  the  average  amount  of  typhoid 
fever  in  all  the  cities  excepting  Lowell  and  Lawrence  was 
very  much  the  same.  All  the  tables,  however,  display  a 
marked  excess  of  typhoid  fever  in  Lowell  and  Lawrence 
over  that  in  the  other  cities,  and  in  the  year  of  the  great 
epidemic  (1890-1891)  this  excess  is  especially  notable. 
Those  who  desire  to  follow  the  facts  in  detail  are  referred 
to  the  original  reports  of  the  author.1  The  main  points, 
however,  will  be  touched  upon  here. 

It  has  already  been  stated  that  these  cities  are  closely 
similar  in  climate  and  pursuits,  and  the  same  thing  may  be 
said  of  them  in  every  other  important  respect  excepting 
one,  namely,  their  water  supply,  which  in  the  cases  of 
Lowell  and  Lawrence  only,  during  these  years  and  for 
some  years  preceding,  had  been  derived  directly  from  the 
Merrimac  River,  a  sewage-polluted  stream,  without  any 
attempt  whatever  at  purification.  The  water  supplies  of 
Concord,  Nashua  and  Haverhill  and,  during  most  of  the 
time,  of  Newburyport,  on  the  other  hand,  were  derived 
from  other  sources,  as  a  rule  entirely  unobjectionable, 
and  in  some  cases,  as  for  example  that  of  Nashua,  re- 
markably pure. 

When  in  the  autumn  of  1890  the  great  epidemic  of 
typhoid  fever  broke  out  in  Lowell,  one  even  more  severe 
soon  after  appeared  in  Lawrence.  The  former  was  traced 
to  an  unusual  infection  of  the  Merrimac  River  by  cases  of 
typhoid  fever  in  a  suburb  of  Lowell,  through  a  little  feeder 
of  the  river  known  as  Stony  Brook,  which  entered  it  only 
three  miles  above  the  intake  of  the  waterworks.  That  in 

1  On  recent  epidemics  of  typhoid  fever  in  the  cities  of  Lowell  and  Lawrence 
due  to  infected  water  supply,  with  observations  on  typhoid  fever  in  other  cities 
and  towns  of  the  Merrimac  valley,  especially  Newburyport.  Illustrated  by 
maps,  photographs,  etc.  Twenty- fourth  Report  (for  1892)  State  Board  of 
Health  of  Massachusetts,  pp.  667-704.  Boston,  1893. 


212     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

the  latter  was  plainly  due  to  the  same  cause,  to  which  was 
added  the  pollution  and  infection  of  the  river  by  the  sew- 
age of  Lowell  (at  that  time  a  city  of  eighty-five  thousand 
inhabitants),  the  sewers  of  which  emptied  into  the  river 
only  nine  miles  above  the  intake  of  the  Lawrence  water- 
works. There  were  all  together  probably  upward  of  fifteen 
hundred  cases  of  the  disease  in  the  two  cities,  as  a  result  of 
this  infection  of  the  public  water  supplies. 

A  number  of  interesting  facts  were  developed  as  the 
result  of  careful  studies  made  of  this  epidemic  by  Mr. 
Hiram  F.  Mills,1  Mr.  George  V.  McLauthlin,  and  the 
author.  It  was  discovered,  for  example,  by  Mr.  Mills, 
that  Lowell  and  Lawrence  had  long  suffered  annually 
from  two  autumn  increments  of  typhoid  fever,  instead  of 
one  as  is  customary  in  most  places,  and  that  the  first  was 
contemporaneous  with  that  in  other  cities  and  towns  of  the 
state,  while  the  second  arrived  considerably  later.  The 
latter  was  evidently  due  to  the  fact  that  the  water  supplies 
of  the  two  cities  had  become  infected  as  a  result  of  the 
usual  autumn  increment  of  the  disease  in  the  cities  and 
towns  on  the  river  above,  so  that  the  second  increment 
was  a  crop  of  which  the  first  was  the  seed. 

It  was  discovered  by  the  author  that  the  problem  of 
typhoid  fever  in  these  cities  was  much  complicated  by  the 
prevailing  custom  in  both  of  distributing  in  the  numer- 
ous mills  and  factories  water  so  placed  as  to  be  acces- 
sible for  drinking  purposes  (and  in  fact  much  used  by 
the  operatives  of  whom  the  population  is  largely  com- 

1  To  Mr.  Mills,  the  distinguished  hydraulic  engineer,  whose  paper  largely 
devoted  to  this  epidemic  ("  Typhoid  Fever  in  its  Relation  to  Water  Supplies," 
Twenty-second  Annual  Report  State  Board  of  Health  of  Massachusetts,  for 
1890,  pp.  525-543)  is  of  great  interest  and  value,  sanitary  science  is  under 
deep  obligations  for  many  years  of  able,  disinterested,  volunteer  service. 
In  Mr.  McLauthlin,  whose  early  death  cut  short  a  career  of  unusually  brilliant 
promise,  sanitary  science  lost  an  enthusiastic,  devoted  and  tireless  worker, 
whose  labors  in  epidemiology  for  the  State  Board  of  Health  of  Massachusetts 
deserve  remembrance. 


TYPHOID   FEVER   IN   LOWELL   AND   LAWRENCE    213 

posed),  which  was  derived  directly  and  unpurified  from 
little  branches  of  the  river  (called  canals}  used  for  power, 
washing,  etc.,  by  the  mills,  which  were  in  some  cases  pol- 
luted within  the  city  itself  by  excreta  from  other  mills,  the 
public  hospital,  privies,  etc. 

The  Lowell  and  Lawrence  epidemic  of  1890-1891,  on  the 
Merrimac  River,  also  threw  great  light  on  the  interpreta- 
tions properly  to  be  put  upon  chemical  water  analyses,  and 
on  the  theory  of  the  self -purification  of  streams ;  for  the 
chlorine  present  in  the  river  at  Lowell  was  no  greater 
than  that  often  observed  in  good  drinking  water  (owing  to 
the  rising  of  the  river  far  from  the  sea,  the  source  of  the 
chlorine  in  the  natural  waters  of  New  England),  although 
it  was  known  to  have  received  en  route  vast  quantities  of 
sewage  from  the  towns  and  cities  on  its  banks  ;  and  while  it 
had  seemingly  been  purified  by  its  long  journey,  it  was  plain 
from  the  vital  statistics  of  the  two  cities  —  and  especially 
those  of  Lawrence  as  compared  with  Lowell  —  that  puri- 
fication had  been  only  too  incomplete.  Thanks  to  the 
careful  investigations  of  Professor  (now  President)  Drown, 
chemist  of  the  State  Board  of  Health  of  Massachusetts, 
the  former  error  was  easily  detected  by  a  determination  of 
the  "  normal  chlorine  "  of  the  river  at  its  source.  The 
latter  error  (the  seemingly  trustworthy  "  self-purification  ") 
was  readily  accounted  for  by  a  careful  consideration  of  the 
natural  and  heavy  contribution  to  the  river  of  well-filtered 
ground  water,  which  serves  to  dilute,  and  possibly  to 
damage,  but  not  necessarily  to  destroy,  microbic  life. 

§  IO.  — Pollution  versus  Infection 

A  study  of  the  facts  given  in  the  preceding  paragraph 
proves  what  is  now  well  known,  namely,  that  the  use  of 
water  polluted  with  ordinary  sewage  free  from  specific 
infection  is  not  necessarily  followed  by  harmful  conse- 
quences. The  great  sewers  of  the  cities  on  the  Merrimac 


214    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

River  above  Lowell  poured  their  sewage  into  the  river  con- 
stantly, and  yet  at  times  there  was  little  or  no  typhoid 
fever  in  Lowell  After  the  usual  autumn  infection  of  the 
river,  however,  typhoid  fever  abounded  in  Lowell  (and 
later  in  Lawrence);  and  when  in  1890  an  extensive  and 
unusual  infection  occurred  on  a  near  feeder  of  the  Merri- 
mac,  which  had  for  many  years  poured  in  its  sewage  with- 
out marked  effect,  a  great  epidemic  quickly  broke  out  in 
both  cities.  There  is  every  reason  to  believe  that  in  the 
case  of  wells,  springs,  and  other  sources  of  water  supply, 
the  same  law  holds.  Mere  pollution  with  uninfected  sew- 
age, or  with  thoroughly  purified  sewage,  may  do  little  or 
no  harm.  Something  more  than  ordinary  pollution  is  re- 
quired ;  there  must  be  infection  in  the  sewage  and  the 
presence  of  active,  virulent  and  specific  germs  of  disease. 
The  same  thing  is  illustrated  by  the  case  next  to  be  con- 
sidered. 

§11.  —  The  Case  of  Newburyport,  Mass. 

In  January,  1893,  an  outbreak  of  typhoid  fever  in  the 
city  of  Newburyport,  at  the  mouth  of  the  Merrimac, 
furnished  a  striking  and  instructive  demonstration  of  that 
difference  which  exists,  and  is  too  often  forgotten,  between 
general  "pollution"  and  specific  "infection." 

The  city  of  Newburyport  had  for  many  years  derived 
its  drinking  water  from  large  springs  of  an  unobjectionable 
character,  and  typhoid  fever  had  been  of  rare  occurrence 
when  suddenly,  in  January,  1893,  an  unusual  number  of 
cases  of  typhoid  fever  broke  out  almost  simultaneously,  and 
an  investigation  of  them  was  made  by  the  author.  It  soon 
appeared  that  there  were  in  all  about  thirty  cases,  and  on 
inquiry  it  proved  that,  as  the  springs  had  yielded  an  insuffi- 
cient supply  of  water,  a  connection  had  been  made  with 
an  intake  pipe  leading  directly  from  the  Merrimac  River, 
through  which  the  crude  river  water  had  been  pumped  into 
the  pipes.  It  was  also  naively  stated,  by  way  of  defence, 


POLLUTION    VS.   INFECTION  21$ 

that  this  water  could  not  have  caused  the  typhoid  fever 
"  because  the  same  thing  had  been  going  on  since  August." 
Assuming  this  to  be  true,  as  appeared  to  be  the  case,  it  was 
an  extremely  interesting  fact,  because  the  health  records 
of  the  numerous  cities  and  towns  pouring  sewage  into  the 
river  above  Newburyport  showed  very  little  typhoid  fever 
in  any  of  them  in  that  year  until  the  December  just  previ- 
ous, at  which  time  Lowell  once  more  suffered  from  a  small 
epidemic  of  typhoid  fever,  which  seems  to  have  borne 
its  natural  fruit  in  both  Lawrence  and  Newburyport.  In 
other  words,  as  long  as  the  people  of  Newburyport  drank 
the  waters  of  the  Merrimac  merely  polluted  with  ordinary 
sewage,  no  typhoid  fever  (or  other  infectious  disease)  ap- 
peared ;  but  when  the  specific  bowel  discharges  of  typhoid 
fever  were  added  to  the  sewage,  this  disease  speedily  broke 
out.  (See  report  by  the  author  on  the  Newburyport  out- 
break, Twenty-fourth  Annual  Report  State  Board  of  Health 
of  Massachusetts  (for  1892),  pp.  701-704.) 

From  this  and  many  other  similar  cases  we  have  reason 
to  believe  that  sewage-polluted  water  is  ordinarily  only  a 
vehicle,  and  not  usually  in  itself  a  source,  of  infectious 
disease. 

§  12. —  An  Epidemic  of  Asiatic  Cholera  in  Hambrirg,  Ger- 
many, traced  to  an  Infected  Public  Water  Supply 

The  great  epidemic  of  Asiatic  cholera  which  occurred  in 
Hamburg  in  1892  was  traced  to  an  infection  of  the  public 
water  supply,  probably  due  to  the  excrements  of  certain 
emigrants  detained  on  ships  in  the  Elbe  while  en  route  to 
America,  and  suffering  from  the  disease  in  question.  The 
water  supply  of  Hamburg  was  at  that  time  derived  directly 
from  the  Elbe,  and  pumped,  without  purification  of  any 
kind,  for  the  immediate  use  of  the  citizens.  A  neighboring 
suburb  (Wandsbeck)  and  the  city  of  Altona  which  forms 
virtually  a  part  of  Hamburg,  remained  almost  entirely  free 
from  the  disease.  The  former  had  an  excellent  water  sup- 


216    WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

ply  not  drawn  from  the  river ;  the  latter  drew  its  water 
supply  from  the  river,  and  from  a  point  where  it  contained 
more  sewage  than  did  the  Hamburg  water,  but  with  this 
difference  :  —  the  Altona  water  supply  was  purified  by 
filtration  before  it  was  delivered  to  the  consumers.  Since 
the  epidemic,  Hamburg  has  also  introduced  excellent 
filters,  with  most  satisfactory  results. 

§  13. — An  Epidemic  of  Typhoid  Fever  in  New  Haven, 
Conn.,  due  to  an  Infected  Surface  Water  Supply 

In  the  spring  of  1901,  typhoid  fever  appeared  in  excess 
in  one  portion  of  the  city  of  New  Haven,  Conn.,  which 
was  served  by  a  water  supply  distinct  from  those  supplies 
serving  the  remainder  of  the  city.  In  all  about  450  cases 
appeared  within  one  month.  Investigation  showed  that 
the  outbreak  was,  in  kind,  not  unlike  that  in  Plymouth, 
Penn.  (described  above).  The  excrements  of  typhoid  fever 
patients  in  a  single  house  had  found  their  way  during 
heavy  rains  into  a  reservoir,  which  had  previously  been 
drawn  low,  so  that  the  infection  was  carried  quickly,  and 
while  comparatively  fresh,  to  the  consumers  of  the  water, 
with  disastrous  results. 

§  14. — Diseases   Other  than    Typhoid  Fever  and  Asiatic 
Cholera  traced  to  Polluted  Drinking   Waters 

It  is  an  interesting  and  very  important  question  whether 
or  not  diseases,  other  than  those  already  described,  are 
capable  of  transmission  by  drinking  water,  and  we  are  at 
present  unable  to  answer  the  question  satisfactorily.  It 
is  easy  to  see  that  much  must  depend  on  the  conditions 
surrounding  any  particular  case.  For  example,  cholera  in- 
fantum,  diphtheria  and  measles  are  seldom,  if  ever,  charged 
to  polluted  water  supplies,  and  yet  there  is  very  little  doubt 
that  if  the  stay  in  the  water  of  their  germs  should  be  short 
enough,  the  germs  would  survive  and  do  their  character- 


WATER-BORNE   DISEASES  2 1/ 

istic  damage.  The  truth  appears  to  be  that  water  is  a 
much  less  favorable  vehicle  for  some  germs  —  such  as 
those  of  diphtheria  —  than  for  others  —  such  as  those  of 
typhoid  fever ;  but  in  the  present  state  of  our  ignorance  it 
would  be  very  rash  to  conclude  that  any  particular  germs 
may  not,  under  favorable  circumstances,  be  conveyed  by 
drinking  water  acting  as  a  vehicle. 

§  15. — Dysentery  and  Diarrhcea 

In  the  case  of  dysentery  and  diarrhoea,  there  is  no  doubt 
whatever  that  drinking  water  may  be,  and  often  is,  their 
ready  vehicle.  In  almost  all  cases  in  which  a  pure  water 
supply  has  been  substituted  for  one  impure,  a  marked 
diminution  can  be  shown  in  the  deaths  attributed  to  these 
disorders.1 

Previous  to  the  improvement  of  the  water  supply  of 
Burlington,  Vt.,  in  1894,  dysentery,  and  especially  diar- 
rhoea, were  relatively  prominent  among  the  assigned  causes 
of  mortality;  but  since  that  time  they  have  been  insig- 
nificant. The  case  of  Burlington,2  in  respect  to  diarrhoea, 
is  peculiarly  instructive.  References  to  the  local  sanitary 
conditions  of  that  city  will  be  found  on  pp.  132,  234.  In 
this  connection  it  will  suffice  to  state  that  in  the  early 
sanitary  history  of  that  city,  when  the  water  supply  was 
drawn  without  purification  from  a  point  on  the  shore  of 
Lake  Champlain,  relatively  near  the  place  where  the  prin- 
cipal sewer  emptied  into  the  same  lake,  typhoid  fever  and 
diarrhoea  both  prevailed,  after  a  time,  to  an  alarming  de- 
gree. When,  later  (in  1885),  the  main  sewer  outfall  was 
removed  to  a  greater  distance,  typhoid  fever  diminished, 

1  See,  for  example,  Dr.  Buchanan's  classical  report,  Ninth  Report  Medical 
Officer  of  the  Privy  Council,  p.  16.     London,  1867. 

2  See,  on  this  subject,  the  author's  paper,  "  On  the  Sanitary  Condition, 
Past  and  Present,  of  the  Water  Supply  of  Burlington,  Vt."     Journal,  New 
England  Waterworks  Association,  Vol.  X,  No.  3,  pp.  167-183. 


218     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

but  diarrhoea  remained  very  prevalent.  When,  still  later, 
in  1894,  the  sewage  outfall  and  the  water  intake  were  still 
further  separated,  —  the  water  intake  having  been  carried 
out  some  three  miles  into  "  the  broad  lake,"  —  endemic 
diarrhoea  also  disappeared. 

§  1 6.  —  Concluding   Remarks   on  Drinking    Water    as  a 
Vehicle  of  Disease 

Space  forbids  extended  treatment  in  this  connection  of 
many  minor  principles  which  have  been  worked  out  along 
the  line  of  the  epidemiology  of  diseases  conveyed  by  water. 
A  few  of  these  may,  however,  be  set  down.  One. is  that 
the  intensity  of  the  epidemic  appears  to  depend  largely  on  the 
amount  and  the  freshness  of  the  infection.  That  it  depends 
on  the  amount  is  clear  from  the  fact  that  the  size  of  the  epi- 
demics in  Lawrence  followed  obviously  the  size  of  the  cor- 
responding serious  outbreaks  in  Lowell.  That  it  depends 
on  the  freshness  of  the  infection  is  shown,  for  example,  by 
the  tremendous  effect  upon  Lowell  of  a  small  but  near 
infection,  while  the  same  city  had  annually  been  exposed, 
without  much  doubt,  especially  in  the  autumn,  to  more 
extensive,  but  at  the  same  time  more  remote,  infection. 
The  same  thing  is  shown  by  the  experience  of  Chicago. 
So  long  as  water  was  derived  from  the  two-mile  crib,  com- 
paratively little  typhoid  fever  developed;  but  when,  in 
1891,  water  was  drawn  so  that  more  and  fresher  germs 
were  received,  an  epidemic  of  the  most  serious  and  threat- 
ening character  appeared.1 

Another  interesting  series  of  facts  appears  when  we  con- 
sider the  local  conditions  on  the  Merrimac  above  Lowell. 
Inasmuch  as  the  river  is  very  low  in  summer,  so  that  for 
weeks  at  a  time  it  is  wholly  diverted  into  the  canals  at 
Lowell  and  Lawrence  to  be  used  for  power  in  the  mills, 

1  Sedgwick  and  Hazen,  "Typhoid  Fever  in  Chicago."  Engineering  News, 
New  York,  April,  1892. 


TYPHOID  FEVER  IN   CHICAGO  2 19 

and  inasmuch,  further,  as  the  sewers  of  the  cities  above 
these  are  constantly  pouring  their  sewage  into  the  river,  it 
follows  as  a  matter  of  course  that  at  such  times  the  amount 
of  sewage  in  the  river  is  relatively  greater  than  at  other 
times.  It  might,  therefore,  reasonably  be  supposed  that  a 
sewage-borne  disease,  such  as  typhoid  fever,  ought  to  be 
more  abundant  among  those  using  the  water  at  such  times. 
It  would  also  be  expected  that  the  bacteria  which  swarm 
so  abundantly  in  sewage  must  be  abnormally  numerous  in 
the  river  water  at  a  time  when  sewage  forms  so  large  an 
element  in  its  composition. 

The  facts,  however,  are  precisely  the  reverse  of  what 
might  at  first  sight  have  been  reasonably  expected. 
Typhoid  fever  was  comparatively  rare  among  users  of  the 
Merrimac  when  the  river  was  "  low "  and  concentrated, 
and  frequent  when  the  river  was  "  high  "  and  the  sewage 
dilute.  Bacteria  were  also  few,  comparatively.  On  looking 
for  the  explanation  of  these  facts  it  was  found  in  the  local 
conditions.  It  appears  that  when  the  river  is  "low," 
although  the  sewage  which  it  contains  forms  a  larger  pro- 
portion of  its  whole  volume  than  at  other  times,  yet  the 
river  then  becomes  a  series  of  comparatively  quiet  mill- 
ponds,  fed  largely  by  the  purest  water  which  ever  enters 
the  river,  namely,  well-filtered  ground  water  nearly  free 
from  bacteria.  Purified  partly  by  dilution  with  this  purer 
ground-water,  and  partly  by  the  intense  and  long  light  of 
summer  days,  by  sedimentation  in  the  relatively  slow  and 
quiet  stream,  and  probably  also  by  the  action  of  larger 
micro-organisms  such  as  algae  and  infusoria,  and  even  by 
higher  plants  such  as  Anacharis  or  Vallisneria,  it  finally 
comes  to  pass  that  the  summer  flowage  is  actually  safer  to 
drink  than  the  impetuous  freshets  of  the  spring  or  autumn, 
which,  though  largely  composed  of  rain  water,  in  their  vio- 
lence corrode  the  surface  of  the  earth,  and  bear  swiftly  to 
the  consumer  of  the  river  water  not  only  the  foul  washings  of 
the  surface  soil,  but  also,  with  small  opportunity  for  purifi- 


220     WATER  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

cation,  the  fresh  sewage  of  even  remote  cities  and  towns.1 
Hence  the  paradox,  that  when  river  water  is  freshest,  it 
may  be  least  safe ;  and  when  richest  in  sewage,  it  is  not 
necessarily  most  dangerous. 

The  student  of  sanitary  science  is  strongly  advised  to 
study  in  the  most  minute  detail  and,  if  possible,  under  a 
master  in  epidemiology,  at  least  one  epidemic  of  typhoid 
fever.  Such  epidemiological  work  is  to  the  sanitarian  what 
careful  laboratory  work  is  to  the  chemist,  the  physicist  or 
the  biologist. 

1  For  an  interesting  and  instructive  example  of  the  efficiency  of  relatively 
small  and  remote  pollutions,  see  a  report  by  the  author  on  "  The  Sources  of 
Typhoid  Fever  in  Pittsburgh."  Report  of  the  Filtration  Commission  of  the 
City  of  Pittsburgh,  Penn.  Pittsburgh,  1899. 


CHAPTER   IX 

ON   THE   ESTABLISHMENT  AND   CONSERVATION   OF   PURITY  IN 
PUBLIC   WATER    SUPPLIES1 

"  There  is  no  river  in  the  United  Kingdom  long  enough  to  secure 
the  oxidation  and  destruction  of  any  sewage  which  may  be  discharged 
into  it,  even  at  its  source."  Rivers  Pollution  Commission  of  1868, 
Sixth  Report,  p.  427.  London,  1874. 

"The  public  is  hitherto  very  imperfectly  protected  against  certain 
extreme  dangers  which  the  malfeasance  of  a  water  company,  supplying 
perhaps  half  a  million  of  customers,  may  suddenly  bring  upon  great 
masses  of  population.  Its  colossal  power  of  life  and  death  is  something 
for  which  till  recently  there  has  been  no  precedent  in  the  history  of  the 
world  ;  and  such  a  power,  in  whatever  hands  it  is  rested,  ought  most 
sedulously  to  be  guarded  against  abuse.1' — SIR  JOHN  SIMON,  Ninth 
Report  of  the  Medical  Officer  to  the  Pri-vy  Council,  p.  28.  London, 
1867. 

§  I.  —  Public  Supplies  as  Ptiblic  Dangers 

A  PUBLIC  supply  is  a  public  danger,  and  for  two  reasons: 
first,  because  it  affects  large  numbers  of  people;  and,  second, 
because  it  is  beyond  their  direct  supervision  and  control. 
Along  with  the  substitution  of  the  convenience  of  public, 
for  the  inconvenience  of  private,  supplies  of  gas,  water,  milk 
and  transportation,  goes  inevitably  the  surrender  of  the 
privilege  of  private  supervision  and  superintendence.  This 
is  one  of  the  obvious  disadvantages  of  urban  life  every- 
where, and  especially  of  life  in  great  cities.  The  social  unit 
—  the  family  —  can  as  a  rule  no  longer  use  its  own  well,  its 
own  cow,  its  own  carriage.  It  must  depend  as  a  rule  upon 

1  Originally  prepared  by  the  author  as  the  "  Middleton  Goldsmith  "  lecture 
of  the  New  York  Pathological  Society,  and  read  by  him  before  the  Society, 
March  15,  1898. 

221 


222  PURITY    IN    PUBLIC   WATER    SUPPLIES 

the  public  water  supply,  the  public  gas  supply,  the  public 
milk  supply,  the  public  vehicle.  These,  of  course,  are  often 
cheaper  and  more  convenient,  but,  unhappily,  often  also 
more  dangerous. 

On  the  other  hand,  it  is  easy  to  see  that  public  sup- 
plies may  easily  be  made  public  safeguards.  All  that  is 
necessary  is  to  substitute  for  private  supervision  and  pri- 
vate control  such  expert  and  scientific  superintendence  as 
the  danger  involved  demands,  and,  so  far  as  public  sup- 
plies are  concerned,  a  condition  of  the  whole  may  often 
be  obtained  far  superior  to  any  within  the  reach  of  a  single 
member  or  family  of  the  community.  It  cannot,  therefore, 
be  too  soon  or  too  plainly  understood  that  common  sense, 
as  well  as  science,  absolutely  requires  from  great  cities  the 
most  expert  public  supervision  attainable,  in  place  of  pri- 
vate supervision  surrendered.  This  surrender,  indeed,  is 
not  unconditional.  If  public  service  cannot  or  does  not 
secure  or  provide  such  adequate  and  expert  supervision, 
there  will  be  a  return  to  the  more  primitive  state.  Intelli- 
gent families  will  prefer  country  to  urban  life,  and  private 
to  public  supervision.  The  rapid  growth  of  suburban  pop- 
ulations, sometimes  at  the  expense  of  the  more  urban,  may 
be  already,  in  part  at  least,  due  to  the  lack  of  such  ade- 
quate supervision  in  great  cities. 

The  most  important  public  supplies  of  cities  are  food, 
drink  and  air.  Of  these  the  water  supply  is  easily  of 
the  first  importance  to  the  sanitarian,  for  the  reason  that 
the  air  supply  is  as  yet  beyond  his  control,  while  the 
food  supply,  with  a  few  exceptions,  such  as  milk,  raw 
oysters  and  certain  fruits  and  vegetables,  is  purified  by 
cookery  before  it  is  swallowed.  Water,  on  the  other  hand, 
is  swallowed  raw,  often  (relatively  speaking)  in  very  large 
quantities,  and  it  is  now  universally  admitted  that  impure 
drinking  water  is  a  ready  vehicle  of  disease. 

It  is  one  of  the  immense  advantages  of  the  zymotoxic 
theory  of  infectious  disease  that  it  has  made  easy  of  com- 


PUBLIC   SUPPLIES   AS  PUBLIC  DANGERS          223 

prehension  the  precise  method  of  conveyance  of  disease 
germs.  At  the  same  time  it  is  no  less  valuable  in  other 
directions,  since  it  makes  it  possible,  at  least  for  experts, 
to  understand  why  some  diseases  are,  and  some  are  not, 
readily  conveyed  by  water ;  how,  precisely,  impurity  arises ; 
how  impurity  may  be  avoided  or  overcome,  and  purity  es- 
tablished ;  and  finally,  how  purity,  having  been  once  estab- 
lished, may  be  effectually  or  ineffectually  conserved.  When 
we  consider  the  enormous  quantities  of  water  required  by 
large  cities,  most  of  which  is  not  used  for  drinking,  but  all 
of  which  must  be  fit  to  drink,1  we  may  readily  appreciate 
the  importance  of  the  subject  with  which  this  lecture  deals. 

§  2.  —  The  Atmosphere  as  the  Source  of  Water  Supply 

The  ultimate  source  of  all  water  supply,  public  or  pri- 
vate, is  the  atmosphere,  in  which  the  vapor  of  water 
(derived  from  land  or  sea)  is  condensed  and  precipitated 
as  rain,  snow,  dew  or  fog.  Theoretically,  every  rain-drop 
must  form  about  some  material  particle,  and  the  only  par- 
ticles of  this  kind  in  the  atmosphere  are  particles  of  dust. 
Dust  particles  are  frequently  largely  composed  of  the 
bodies  of  micro-organisms,  and  hence  it  follows  that  at  the 
very  instant  of  its  birth  the  rain-drop  may  enclose  one  or 
many  micro-organisms.  On  the  other  hand,  such  bacterial 
bodies  may  not  be  alive,  but  dead;  and  dust  consists  of 
many  other  things  than  micro-organisms,  bits  of  inorganic 
matter  and  organic,  though  unorganized,  particles,  so  that 
only  a  few  rain-drops,  probably,  can  be  conceived  of  as 
including  micro-organisms,  still  less  living  micro-organisms, 
at  the  start.  Again,  it  must  not  be  forgotten  that  even  if 
we  assume  the  presence  of  some  living  micro-organisms  in 

1  In  the  United  States  it  has  not  usually  been  considered  advisable  to 
install  two  systems  of  water  supply,  one  potable  and  one  non-potable.  This 
is  done,  however,  in  some  places,  eg.  in  Paris.  See  on  this  subject  Special 
Report,  Mass.  State  Board  of  Health,  upon  a  Metropolitan  Water  Supply, 
p.  217.  Boston,  1895. 


224  PURITY   IN   PUBLIC  WATER   SUPPLIES 

rain-drops,  these  are  doubtless,  with  the  rarest  exceptions, 
saphrophytic  and  not  pathogenic.  Our  present  knowledge 
of  the  behavior  of  pathogenic  germs  in  the  air  is  very 
limited,  and  this  is  particularly  the  case  with  those  dis- 
eases, such  as  typhoid  fever  and  Asiatic  cholera,  which  are 
oftenest  water-borne.  Granting,  however,  the  possibility 
of  their  presence  in  air,  and  the  possible  concurrence  of 
soluble  organic  particles,  it  is  obvious  that  a  drop  of  such 
naturally  distilled  water  may  become  polluted  and  even 
infected  from  its  very  birth.  As  it  falls  into  the  lower 
layers  of  the  atmosphere,  richer  in  dust,  the  chance  of 
such  pollution  must  necessarily  increase  pari  passu.  The 
possibility  of  such  atmospheric  contamination  of  water, 
and  even  its  infection,  must  never  be  forgotten,  but  yet 
cannot  be  regarded,  in  the  present  state  of  our  knowledge, 
except  in  very  rare  and  unusual  cases,  as  important. 

§  3.  —  The  Pollution  of  Rain-water  and  Snow  by  Dust 

The  phenomena  afforded  by  snow  deserve  especial, 
though  brief,  mention  in  this  connection.  A  snowflake, 
especially  if  moist,  appears  to  be  a  kind  of  filter  through 
which  a  relatively  large  amount  of  air  passes  as  the  snow- 
flake  falls;  and  this  peculiarity  of  structure  doubtless 
explains  the  fact  that  snow,  particularly  that  first  to  fall,  is 
often  really  dirty  and  rich  in  micro-organisms ;  while,  at  the 
same  time,  the  atmosphere  after  a  prolonged  snowfall  is 
bacterially,  as  well  as  to  the  senses,  noticeably  purified. 
It  follows  as  a  matter  of  course  that  melted  snow  or  snow 
water  —  and,  we  may  add,  snow  ice  —  is  far  from  pure; 
and  that  the  water  derived  from  melted  snow  in  periods  of 
"thaw"  is  not,  as  it  might  be  supposed  to  be,  particularly 
pure.  On  the  contrary,  the  author  observed  on  one  oc- 
casion, when  a  sudden  thaw  had  poured  vast  quantities 
of  such  water  into  the  Merrimac  River,  the  largest  number 
of  bacteria  he  ever  discovered  in  the  city  water  of  Lowell, 


MICROBES   IN   RAIN-DROPS   AND   SNOWFLAKES     225 

viz.,  33,000  per  cubic  centimetre  —  a  number  far  in  excess 
of  that  observed  when  the  spring  freshets  had  polluted  the 
river,  or  in  summer,  when  the  proportion  of  sewage  to  other 
water  in  the  river  is  highest. 

If,  however,  proof  were  needed  that  typhoid  fever  and 
other  diarrhoeal  diseases  can  be  conveyed  otherwise  than 
by  water  supplies  drawn  through  or  over  the  earth,  it 
would  be  enough  to  mention  those  places,  such  as  Ber- 
muda, where  water  is  obtained  for  drinking  only  from 
cisterns  or  cemented  basins  on  the  hills,  in  which  rain- 
water only  is  collected,  and  where,  nevertheless,  typhoid 
fever  is  by  no  means  unknown  either  among  the  troops  or 
the  citizens.  It  hardly  needs  to  be  added  that  such  fever 
is  probably  not  attributable  to  drinking  water. 

§  4.  — Influence  of  the  Earth  upon  the  Purity  of  Rain-water 

Once  the  rain-drop,  alone  or  combined  with  others, 
touches  the  surface  of  the  earth  or  its  appurtenances  — 
such  as  rocks,  trees,  roofs,  fences,  haystacks,  animals  —  it 
meets,  almost  immediately,  abundant  dust  or  dirt,  including 
matters  organic  and  inorganic,  soluble  and  insoluble,  living 
and  lifeless.  As  it  rolls  over  the  dusty  rock  alone,  or  with 
others  forming  a  trickling  stream,  it  naturally  dissolves 
some  substances  and  sweeps  on  others  mechanically  —  its 
departure  from  purity  increasing  as  it  proceeds.  If  it 
wears  away  the  soil,  enough  of  the  latter  may  be  carried 
along  to  make  it  discolored  or  even  muddy,  no  chemical 
analysis  of  such  water  being  needed  to  show  its  pollution, 
while  bacterially  it  is  charged  with  thousands  of  micro- 
organisms in  every  cubic  centimetre.  This  is  its  horizon- 
tal or  surface-displacement  history.  If,  on  the  contrary, 
the  rain-drop  falls  upon  porous,  absorbent  earth,  not  already 
water-logged,  it  will  sink  by  gravity,  possibly  also  by  capil- 
larity, or  by  the  push  of  other  particles  from  behind,  down 
into  the  spongy  earth.  This  will  be  a  vertical  displace- 
Q 


226  PURITY  IN   PUBLIC  WATER   SUPPLIES 

ment ;  and  here,  also,  it  will  as  a  rule  come  into  contact 
with  matters  organic  and  inorganic,  soluble  and  insoluble, 
living  and  lifeless.  Whether  its  alighting  place  be  sand 
or  soil,  it  will  usually  find  the  porous  earthy  particles 
mantled  with  bacterial  jelly,  dead  or  alive,  wet  or  dry. 
And  immediately  actions  and  reactions,  physical  and 
chemical,  will  begin,  and  continue  until  a  new  condition 
has  arisen.  Water,  that  thus  on  touching  the  earth  takes 
the  vertical  direction,  is  commonly  called  "  ground  "  water ; 
while  that  which  quickly  moves  off  more  or  less  horizontally 
is  called  "  surface  "  water.  Both,  it  will  be  observed,  are 
comparatively  impure  when  they  arrive  on  the  earth ;  that 
is  to  say,  they  consist  of  pure  water  holding  in  solution 
and  suspension  certain  organic  and  inorganic,  living  and 
lifeless,  substances  derived  from  the  atmosphere. 

This  is  perhaps  the  best  place  to  remark  that  the  terms 
"pure"  and  "impure"  are  relative  only.  We  have  thus  far 
used  these  terms  in  the  chemical  sense,  yet,  in  the  popular 
sense,  rain-water  is  remarkably  pure.  We  may  allow  the 
popular  meaning  and  still  keep  in  mind  the  fact  that  rain- 
water, from  the  chemical  and  bacterial  point  of  view,  is 
of  relative  purity  only.  From  this  point  onward,  it  will  be 
convenient  if  we  consider  separately  the  two  great  classes 
of  natural  waters,  namely,  "  ground  "  waters  and  "  surface  " 
waters. 

§  5.  —  Rain-water  and  the  Living  Earth.     Ground  Waters 
and  their  Pollution  and  Purification 

Rain-water  on  entering  porous  earth  (either  sand  or  soil 
open  or  close  in  texture)  is  at  once  brought  under  new 
conditions  and  into  close  contact  with  swarming  bacterial 
life.  The  earth  is  the  home  of  the  bacteria.  They  are 
found  in  the  air,  but  only  because  they  have  been  lifted 
into  it  by  winds,  in  the  form  of  dried  earth  or  dust.  They 
are  found  in  water,  —  in  streams,  lakes  and  the  sea,  —  but 
seldom  in  density  of  population  at  all  comparable  to  that 


RAIN   AND   THE   LIVING  EARTH  227 

existing  in  the  surface  layers  of  the  earth.  The  reason  for 
this  seems  to  be  that  at  the  surface  of  the  earth  bacteria 
secure  at  the  same  time  oxygen,  moisture  and  food  —  the 
most  favorable  conditions  for  their  life.  It  appears  to  be 
very  doubtful  if  bacteria  are  preeminently  aquatic.  Many 
species  at  any  rate  seem  to  inhabit  the  surface  layers  of 
the  earth,  and  if,  as  appears  to  be  the  case,  they  are  largely 
and  perhaps  preferably  terrestrial,  this,  as  we  shall  see,  is  a 
matter  of  great  consequence  in  the  establishment  and  con- 
servation of  the  purity  of  waters. 

The  rain-drop  arriving  upon  the  porous  earth  is  at  once 
greeted  by  a  hungry  population  of  bacteria  mantling  the 
sand  grains  over  which  it  is  spread ;  and  this,  too,  a  perma- 
nent, not  a  nomadic,  population.  More  or  less  slowly  it 
sinks  through  this  living,  gelatinous  layer,  and  as  it  passes 
on  it  is  robbed  of  its  suspended  organic  matters  and  of  some 
of  those  in  solution.  It  is  also  mechanically  filtered  to  some 
extent,  no  doubt ;  but  the  main  thing  is  that  as  a  result  of 
its  journey,  it  is  so  purified  in  respect  to  its  organic  matters 
that  it  can  no  longer  support  abundant  bacterial  life.  Mean- 
while it  readily  dissolves  the  end-results  and  the  by-products 
of  the  luxuriant  bacterial  vegetation  through  which  it  passes, 
and  becomes  the  vehicle  of  nitrates,  sulphates  and  other 
mineral  matters.  As  it  sinks  lower  and  lower,  it  dissolves 
more  and  more  of  such  salts,  and,  passing  by  other  resident 
bacteria,  is  increasingly  purified  of  organic  matters  capable 
of  supporting  bacterial  life.  Such  water  may  contain  bac- 
teria, but,  as  abundant  experiments  have  shown,  these  are 
relatively  few  in  number  and  singularly  slow  of  develop- 
ment. Water  derived  from  deep  wells  is  generally  poor  in 
bacteria,  and  even  when  not  poor,  is  characterized  by  cer- 
tain peculiarities  which  remove  it  from  the  category  of 
waters  charged  with  ordinary  bacteria.  In  the  case  of  most 
ground  waters,  a  high  degree  of  organic  purity  is  estab- 
lished by  the  natural  processes  just  described ;  and  if  such 
waters  be  collected  in  protected  springs,  wells,  or  covered 


228  PURITY   IN   PUBLIC   WATER   SUPPLIES 

reservoirs  properly  constructed,  their  organic  purity  is 
readily  conserved,  and  they  constitute  (in  such  cases)  some 
of  the  most  satisfactory  water  supplies  known. 

There  are,  however,  certain  conditions  which  limit  the 
usefulness  of  "  ground  "  waters.  In  the  first  place,  while 
of  high  organic  purity,  they  may  have  become  so  rich  in 
inorganic  matters  as  to  belong  to  the  class  of  "  hard " 
or  "  mineral "  waters,  which,  by  common  consent,  based 
upon  general  experience,  places  them  in  the  category  of 
undesirable  waters,  inferior  for  public  supplies.  Far  more 
important,  however,  is  the  fact  that  such  waters  are  neces- 
sarily limited  in  quantity  and,  therefore,  not  often  available 
for  great  cities.  Obviously  ground  water  can  occupy  only 
the  interstices  of  the  earth's  crust,  is  subject  when  drawn 
upon  to  high  friction,  and  therefore  moves  with  slow  veloc- 
ity, so  that  from  any  one  point,  or  from  a  few,  only  a 
limited  amount  of  water,  and  that  at  a  low  rate  of  flow, 
can  safely  be  counted  upon.  Great  cities,  however,  require 
large  quantities  of  water,  and  often  large  quantities  within 
a  very  short  time ;  so  that  it  is  easy  to  see  why,  for  them, 
ground  waters,  will  seldom,  if  ever,  be  adequate  sources  of 
supply. 

On  the  other  hand,  ground  waters  may  be  polluted 
instead  of  purified  by  their  passage  through  the  earth. 
If  the  earth  is  itself  impure  or  overtaxed  from  leaky  cess- 
pools, sink  drains  or  other  sources  of  foulness,  natural  puri- 
fication may  give  way  to  unnatural  pollution.  This  is  the 
accepted  theory  of  the  pollution  of  domestic  wells.  But, 
in  view  of  the  remarkable  purifying  powers  of  the  earth, 
and  the  almost  total  lack  of  satisfactory  evidence  of  disease 
arising  from  pollution  thus  effected,  the  author  is  strongly 
of  the  opinion  that  the  damage  done  by  underground  pol- 
lution of  domestic  wells  has  been  greatly  exaggerated. 
Excepting  in  those  rare  cases  of  fissures  in  the  earth  which 
give  easy  access  for  pollution  from  the  surface,  and  except- 
ing pollutions  which  have  come  in  from  the  open  top,  he 


OBJECTIONS  TO   GROUND-WATER   SUPPLIES      229 

is,  and  long  has  been,  very  sceptical  concerning  much  of 
the  damage  attributed  to  domestic  wells.  It  is  very  much 
to  be  feared  that  more  harm  has  been  done  in  these  cases 
by  throwing  investigators  off  the  true  scent  than  by  the 
pollutions  themselves,  real  or  imaginary. 

Much  more  serious  than  pollutions  of  the  soil  are  the 
dangers  of  infection  of  ground  waters  from  workmen 
within  wells  themselves,  such  as  happened,  for  example, 
in  the  well-known  Caterham  (England)  case  reported 
upon  by  Dr.  Thorne-Thorne.  In  this  instance  it  ap- 
peared that  the  bowel  discharges  of  an  incipient  or 
"  walking  "  typhoid  patient,  a  laborer  in  one  of  the  open 
wells  supplying  the  towns  of  Caterham  and  Red  Hill, 
found  direct  access  to  the  pipes,  and  brought  on  a  severe 
and  widespread  epidemic  among  users  of  this  ground-water 
supply.  (For  an  account  of  this  epidemic,  see  pp.  191- 
200.) 

§  6.  —  The  Conservation  of  Purity  of  Ground  Waters 

Finally,  ground  waters  have  the  serious  defect,  that  in 
order  to  remain  pure  after  collection,  they  often  require  to 
be  kept  in  the  dark.  The  cities  of  Newton  and  Brook- 
line,  Mass.,  derive  ground-water  supplies  of  great  or- 
ganic purity  from  driven  wells  in  an  uninhabited  district 
of  the  Charles  River  valley.  But  in  order  to  conserve  a 
purity  established  by  natural  filtration,  these  cities  have 
had  to  build  costly  covered  reservoirs ;  because  on  expos- 
ure to  the  light,  such  ground  waters  become  infested  with 
chlorophyl-bearing  microscopical  organisms,  (diatoms,  des- 
mids,  etc.),  which  in  turn  support  noxious  infusorial  ani- 
mals, and  give  rise,  not  infrequently,  to  highly  disagreeable 
and  even  nauseous  tastes  and  odors,  sometimes  described 
by  the  consumers  of  the  waters  as  resembling  "  cucum- 
bers," "fish-oils,"  "pig-pens,"  etc.  The  conservation  of  the 
purity  of  ground  waters  thus  often  becomes  a  matter 
requiring  expert  treatment. 


230  PURITY   IN   PUBLIC   WATER   SUPPLIES 

§  7.  —  Surface    Waters  and  their  Pollution 

Let  us  now  turn  to  that  class  which  we  have  called 
"  surface "  waters,  and  have  described  as  characterized 
by  a  more  or  less  horizontal  movement  of  their  parti- 
cles after  these  have  fallen  upon  the  earth.  In  this  case, 
the  water  which  falls  upon  the  surface,  more  or  less  impure 
from  aerial  pollution,  instead  of  being  subjected  immediately 
to  a  progressive  purification  by  sinking  into  the  earth,  moves 
along  the  surface  of  the  earth,  which  it  erodes,  growing  in 
volume  as  it  proceeds,  and  forming  rills,  rivulets,  or  larger 
streams,  —  brooks,  creeks,  and  rivers,  — which  still  continue 
to  move  along  the  earth's  surface,  exposed  to  all  sorts  of 
pollution,  until  they  pause  for  a  longer  or  shorter  time  in 
ponds  and  lakes,  or  finally  join  the  sea.  The  area  over 
which  this  process  goes  on  is  called  a  "watershed,"  and 
much  of  the  water  which  falls  as  rain  or  snow  is  thus  shed 
off,  as  from  a  roof,  without  ever  having  soaked  into  the 
porous,  purifying  earth. 

But  it  would  be  a  mistake  to  suppose  that  the  entire 
volume  of  brooks,  rivers,  and  lakes  has  been  thus  derived. 
The  greater  part,  even  of  the  so-called  "  surface  "  waters, 
except  in  times  of  freshet  due  to  sudden  thaws  or  to  heavy 
and  prolonged  rain,  is  really  ground  water,  purified  by  a 
shorter  or  longer  passage  through  the  porous  earth.  It  can- 
not be  too  strongly  emphasized  that  a  very  large  portion  of 
the  water  of  all  rivers,  even  of  those  most  polluted,  is  highly 
purified  ground  water ;  and  this  fact  serves  well  to  show 
how  very  impure  the  really  surface-water  portion  of  such 
streams  must  be.  Other  things  equal,  a  water  derived  from 
a  quick-spilling  watershed  must  always  be  relatively  impure 
and  dangerous,  because  to  the  natural  impurities  of  rain 
water  have  been  added  the  surface  impurities  of  the  earth, 
violently  detached  and  rapidly  conveyed. 

It  will  be  clear,  therefore,  at  the  very  outset,  that  the 
problem  of  the  establishment  of  purity  of  surface  water  is 


SOURCES   OF  POLLUTION   OF   SURFACE  WATERS    231 

by  no  means  easy.  At  first  sight  it  would  even  seem  that 
the  larger  a  river  is  the  more  polluted  it  must  be;  for  it 
has  the  longer  been  exposed  to  the  manifold  sources  of 
pollution  on  its  shores  and  from  its  tributaries,  while  as  it 
flows  no  obvious  sources  of  purification  exist.  A  river  to 
the  casual  observer  seems  like  a  great  vena  cava  receiving 
a  host  of  tributary  veins,  each  of  which  has  simply  drained 
its  own  area ;  or  like  a  cloaca,  receiving  drainage  from  a 
thousand  lesser  drains. 


§  8.  —  The  "  Self-purification  of  Streams "  Again 

How,  then,  we  may  well  ask,  did  it  ever  happen  that 
many  well-regulated  American  cities,  some  of  them  of 
large  size,  have  in  the  past  drawn  their  water  supplies 
from  polluted  rivers  or  lakes,  not  heedlessly,  but  on  the 
advice  of  the  ablest  engineers  and  sanitarians  of  the  day  ? 
The  answer  is  that  these  engineers,  in  common  with  the 
best  sanitarians  of  the  time,  trusted  to  a  theory  of  the 
establishment  of  purity  in  surface  waters,  which  we  now 
know  to  have  been  only  a  half-truth  and  utterly  untenable ; 
namely,  the  theory  of  "  self  -purification "  of  streams. 
In  substance  this  theory  was,  that  "  running  water  purifies 
itself."  It  was  based  on  the  obvious  fact  that  a  stream 
befouled  at  a  certain  point  often  shows  no  visible  sign  of 
such  defilement  at  places  some  distance  below.  It  was 
powerfully  supported,  however,  and  seemingly  established 
as  a  law  of  nature,  by  the  chemistry  of  the  day,  which 
sufficed  to  show,  in  correspondence  with  the  evidence  of 
the  senses,  that  there  was  actually  less  organic  matter  at 
the  lower  than  the  higher  point.  Here,  plainly,  was 
actual  scientific  proof  of  purification  —  or  what  seemed 
to  be  such.  Relying  upon  this  theory,  many  cities  —  and 
some  of  them  great  cities  —  in  America  and  elsewhere 
introduced  water  supplies  from  polluted  streams,  relying 
simply  upon  the  self-purifying  power  of  running  water  to 


232  PURITY   IN   PUBLIC   WATER   SUPPLIES 

destroy  the  pollutions  known  to  be  poured  into  the  streams 
at  points  above  (cf.  p.  129). 

To-day  we  realize  that  this  theory  is  only  half  true,  and 
that  such  self-purification  is  only  partial  and  absolutely 
unreliable.  By  a  curious  reversal  of  scientific  opinion,  we 
now  hold  that  it  is  precisely  "  running "  water  which  is 
least  likely  to  purify  itself,  while  stagnant  (standing)  water 
—  formerly  looked  upon  with  dread  and  suspicion  —  is  now 
in  much  favor.  The  old  theory  was  in  vogue  long  enough 
to  enable  us  to  make  a  wonderful  series  of  experiments, 
and  on  a  stupendous  scale  —  experiments  in  which  whole 
cities  confidingly  used  for  years  sewage-polluted  waters, 
often  with  sad  results,  yet  results  of  lasting  instruction  to 
mankind.  Never  again,  so  long  as  civilization  endures,  will 
intelligent  communities,  acting  under  expert  advice,  need 
to  repeat  these  sad  experiments.  The  lesson  was  painful 
and  costly,  but  it  has  been  learned,  and  will  never  be  for- 
gotten. 

The  source  of  error  in  the  earlier  practice  was  in  the 
neglect  of  the  factor  of  dilution,  with  the  assignment 
to  true  purification  and  actual  chemical  change  of  what 
was  really  for  the  most  part  dilution  by  ground  water, 
which,  as  has  been  said  above,  not  only  forms  a  large  pro- 
portion of  the  volume  of  most  rivers,  but  also  brings  to 
them  water  of  a  high  degree  of  organic  purity.  In  so  far 
as  a  mixture  of  pure  water  with  foul  can  purify  the  lat- 
ter, there  is  truly  a  marked  "self-purification"  of  rivers. 
There  is  even  more  than  this  in  fact,  for  some  of  the 
pathogenetic  elements  disappear  en  route  from  cold,  or 
inanition,  or  by  entanglement,  or  by  falling  to  the  bottom, 
or  by  the  germicidal  influence  of  light,  or  from  other  con- 
ditions, all  of  which  may  be  summed  up  in  the  words 
"  unfavorable  environment."  But,  obviously,  the  more 
rapid  the  stream,  the  less  such  conditions  of  whatever 
kind  can  act,  and  the  more  certain  the  damage  likely  to  be 
done  to  the  consumers  of  the  water  below. 


"SELF-PURIFICATION"  IN   STREAMS   AND   LAKES    233 

§  9.  —  Quiet   Watert  not  Running  Water,  Purifies  Itself 

It  is  therefore  not  so  true  that  "  running  "  water,  as  that 
quiet  water,  purifies  itself.  We  may  even  go  so  far  as  to 
say  that  the  first  requirement  for  the  natural  establishment 
of  purity  in  surface  waters  is  quiescence.  But  quiescence 
in  rivers  is  ordinarily  impossible.  Hence  the  establish- 
ment and  conservation  of  purity  in  rapid  rivers  is  to-day 
regarded  as,  by  natural  means,  impossible ;  and  no  river, 
unless  from  an  absolutely  uninhabited  watershed,  is  to  be 
regarded  as  suitable  for  direct  use  as  a  public  water  supply. 


§  10. — Natural  Processes  of  Water  Purification 

Fortunately  there  exist,  nevertheless,  purely  natural  pro- 
cesses by  which  the  water  even  of  polluted  rivers,  though 
not  in  the  rivers  themselves,  can  be  readily  purified  on  a 
large  scale ;  and  it  follows  that  such  streams  may  become 
available,  although  of  course  never  directly,  as  valuable 
sources  of  water  supply,  even  for  great  cities.  The  time 
has  forever  gone  by  when  a  city  or  town  can  honestly 
pump  the  water  of  an  ordinary  river  at  its  doors,  without 
any  previous  purification,  directly  to  its  citizens.  On  the 
other  hand,  we  probably  understand  to-day  better  than 
ever  before  the  nature  of  the  processes  required  to  effect 
the  purification  which  is  s~o  indispensable.  In  fact,  we 
have  abundant  and  positive  evidence,  not  only  from  the 
data  afforded  by  the  bacteriology  of  natural  waters,  but 
also  from  the  actual  experience  of  cities  which  have  used 
such  waters,  that  there  are  purely  natural  processes 
available,  which  under  certain  conditions  are  capable  of 
producing  a  high  degree  of  purification  of  polluted  surface 
waters.  These  processes  are  of  great  scientific  as  well  as 
practical  interest,  and  deserve  our  most  careful,  if  neces- 
sarily brief,  consideration.  We  may  dwell  accordingly, 
first,  upon  the  purification  effected  by  simple  quiescence, 


234  PURITY   IN   PUBLIC  WATER   SUPPLIES 

as  this  is  obtained  in  nature  in  lakes  and  ponds  and  as  it 
can  be  effected,  even  for  rivers,  by  artificial  storage. 

A  case  of  this  first  kind  is  that  afforded  by  the  public 
water  supply  of  Burlington,  Vt.  Burlington  is  the  only 
city  in  New  England  which  derives  its  water  supply  from 
the  same  lake  into  which  it  empties  its  sewage,  although 
this  arrangement  for  water-supply  and  sewage  disposal  is 
common  enough  in  other  parts  of  the  United  States,  such 
as  Chicago  (until  1900),  Milwaukee,  Duluth,  Buffalo,  Cleve- 
land, and  in  Toronto,  Canada.  Burlington  is  situated  at 
the  eastern  extremity  of  a  broad  bay  on  Lake  Champlain, 
and  when,  in  1866,  the  citizens  determined  to  have  an 
ample  public  water  supply  for  fire  and  other  purposes, 
they  naturally  turned  to  the  lake  (cf.  p.  132.) 

The  waterworks  were  built  in  1867,  the  intake  being 
located  on  the  lake  front,  near  the  northern  extremity 
of  the  docks.  For  some  years  the  water  supply  gave 
entire  satisfaction,  and  in  1870  the  health  officer  reported 
that  at  no  time  had  the  city  water  supply  held  so  high  a 
place  in  the  public  estimation.  When  sewers  were  put  in, 
the  trunk  sewer,  carrying  most  of  the  sewage  of  the  city, 
was  made  to  empty  into  the  lake  about  one-half  mile  south 
of  the  water  intake ;  and  although  there  was  gradually  an 
increasing  conviction,  based  upon  the  evidence  drawn  from 
the  prevalence  of  diarrhoea  and  dysentery,  with  a  small 
amount  of  typhoid  fever,  that  things  were  not  altogether 
satisfactory,  matters  did  not  become  bad  enough  to  cause 
the  removal  of  the  sewer  outfall  to  a  more  remote  point 
until  1885,  when  it  was  carried  to  a  place  one  mile, 
instead  of  one-half  mile,  away  from  the  intake  of  the 
waterworks. 

Meantime  the  city  had  increased  in  population,  and  the 
sewer  connections  with  dwellings  had  multiplied ;  but  even 
as  late  as  1892,  while  strongly  disapproving  of  the  local 
conditions,  and  urging  most  emphatically  a  change  in 
them,  the  author  himself,  after  a  very  careful  investigation, 


BURLINGTON ,  VERMONT. 


DIAGRAM    SHOWING   LOCATION  OF    THE 
WATER   INTAKE  AND    SEWER    OUTFALL. 
1895. 


THE   CASE   OF   BURLINGTON,  VERMONT  235 

was  forced  by  the  facts  to  report  to  the  city  officials,  that 
so  great  was  the  purification  accomplished  by  this  one 
mile  of  lake  quiescence  that  there  was  no  immediate 
reason  for  excessive  anxiety  or  alarm  for  the  sanitary 
condition  of  the  water  supply.  He  reported  among  other 
things  that  "the  results  show  conclusively  that  the  mor- 
tality from  typhoid  fever,  —  and  the^ame  is  true  for 
diarrhoea  and  dysentery,  —  has  not  Iren  large  in  Bur- 
lington during  the  last  twelve  years.  The  average  annual 
mortality  from  typhoid  fever  from  1870  to  1891  was 
3.57  per  ten  thousand  inhabitants."  He  then  went  on 
to  show  that  Burlington  compared  favorably  in  this  re- 
spect with  many  cities  having  water  supplies  of  undoubted 
purity,  and  stated  that  in  respect  to  mortality  from  typhoid 
fever  it  had  a  better  record  than  many  cities  having  water 
supplies  of  good  reputation.  He  added,  that  during  the 
past  three  years  he  had  repeatedly  made  bacteriological 
analyses  of  the  Burlington  supply,  and  had  found  no  satis- 
factory evidence  of  the  presence  of  sewage  in  the  drinking 
water.  In  spite  of  these  facts,  however,  he  urged  that  the 
location  of  the  intake  of  the  waterworks  as  near  as  it  was 
to  the  main  sewer  of  the  city  was  highly  objectionable,  if 
not  positively  dangerous,  and  that  he  regarded  it  as  a  con- 
stant menace  to  the  sanitary  welfare  of  the  city. 

Now  how  had  it  happened  that  such  extensive  befouling 
of  the  lake  front,  only  one  mile,  and  for  some  years  only 
one-half  mile,  from  the  intake  of  the  drinking  water  of  the 
city,  had  done  so  little  harm  ?  The  answer  is  that  here, 
precisely  as  in  many  rivers  which  were  formerly  supposed 
to  have  purified  themselves  by  "  running  "  or  exposure  to 
free  oxygen,  dilution  with  pure  water  did  much ;  and,  what 
was  not  true  in  the  case  of  the  rivers,  quiescence  did  far  more. 
Bacterial  analyses  showed  that  at  the  sewer  outfall  the 
numbers  of  bacteria  were  millions,  and  the  kinds  had  clearly 
marked  sewage  characteristics.  But  at  points  one  hun- 
dred feet  away  ninety  per  cent  of  these  had  disappeared, 


236  PURITY   IN   PUBLIC  WATER   SUPPLIES 

and  at  one  thousand  feet  many  more.  At  the  distance  of 
half  a  mile  nearly  all  trace  of  sewage  had  disappeared,  and 
a  mile  away  no  evidence  of  it  could  be  found.  It  should 
not  fail  to  be  stated  that  in  the  Bay  there  are  no  regular 
currents,  but  only  wind  currents  setting  sometimes  in  one 
direction,  sometimes  in  another;  and  that  the  amount  of 
sewage  poured  ii^rom  a  city  of  the  size  of  Burlington  is 
not  very  large,  as^l  then  had  only  about  fifteen  thousand 
inhabitants. 

Furthermore,  the  sewer  outfall  opened  into  a  small 
pocket  or  basin  of  its  own,  where  lively  fermentation 
went  on  in  summer;  and  this  was  an  added  purifying 
agency,  though  dwellers  in  the  neighborhood  complained 
bitterly  at  times  of  the  evil  smells  arising  from  this  little 
basin.  The  fact,  however,  that  in  this  pocket  the  sewage 
lingered  quietly  for  a  time,  and  fermented  more  or  less,  was 
undoubtedly  favorable  to  its  purification.  When,  a  year  or 
two  later,  it  was  determined  to  do  away  with  this  basin,  the 
citizens  were  warned  of  the  added  danger  involved,  and 
finally  were  persuaded  to  carry  the  intake  pipe  of  their 
water  works  three  miles  out  into  the  purer  waters  of  the 
broad  lake. 

It  is  certainly  a  remarkable  and  highly  important  fact, 
that  under  certain  conditions  a  city  or  town  —  but  always 
one  of  small  size  only  —  may  safely  drain  into,  and 
drink  from,  the  same  lake,  —  a  condition  which  may  be 
forcibly  described  as  drinking  from  the  other  side  of  its 
own  cesspool.  This  is,  in  fact,  what  is  done  by  such  cities 
as  Duluth,  Cleveland,  Chicago  (up  to  1900),  and  Mil- 
waukee ;  but  it  is  important  to  remember  that  it  can  be 
done  with  safety  only  by  small  communities,  for  the  reason 
that  the  greater  the  city  the  nearer  we  come  to  a  quick 
circulation — a  river  of  sewage  flowing  out,  a  river  of  water 
flowing  in, — and  the  danger  of  contamination  here  in- 
creases with  the  volumes.  If  it  increases  so  far  as  to  do 
away  with  sufficient  quiescence,  we  have  once  more  estab- 


PURIFICATION   BY   SLOW   SAND   FILTRATION      237 

lished  what  is  essentially  a  stream,  and  running  water,  as 
we  have  seen,  does  not  effectually  purify  itself  —  it  mainly 
undergoes  dilution. 

§  ii. — Purification  by  Storage 

Conversely,  if  a  running  water  such  as  we  have  in  a  river 
can  be  converted  into  a  quiet  water,  —  as  in  a  reservoir, 
—  just  such  purification  as  we  have  discovered  in  Burling- 
ton may  result.  This  is,  indeed,  what  takes  place,  for- 
tunately, with  water  derived  from  polluted  watersheds  and 
stored  in  huge  reservoirs,  —  great  and  often  adequate  puri- 
fication may  be  established  by  prolonged  quiescence,  or 
storage.  There  is  every  reason  to  believe  that  the  princi- 
ples involved  in  the  purification  which  goes  on  in  Burling- 
ton are  typical  in  whole  or  in  part  of  many  other  similar 
cases.  Some  bacteria  perish  almost  immediately  in  the 
cold  water  of  the  lake ;  some  settle  to  the  bottom  and  per- 
ish there ;  some  are  killed  by  light  as  they  float  on  the 
surface;  some  are  devoured  by  predatory  infusoria;  the 
more  hardy  survive,  perhaps,  but  do  not  multiply  because 
of  lack  of  food  and  other  unfavoring  conditions,  and  so 
are  simply  scattered  by  dilution ;  until  finally  only  those 
remain  which  can  permanently  thrive  in  the  now  relatively 
pure  water ;  and  these  are  apparently  mostly  harmless. 

§  12. — Purification  by  Slow  Sand  Filtration 

It  follows  as  a  matter  of  course,  from  what  has  now  been 
said,  that  if  a  city  or  town  must  use  a  river  as  its  source 
of  supply,  it  must  ordinarily  first  purify  it  either  by  natu- 
ral or  by  artificial  means.  One  of  the  natural  processes 
available  has  just  been  described,  and  may  be  summarily 
characterized  as  quiescence  effected  by  prolonged  "stor- 
age." Another  process  may  be  defined  as  "  natural  filtra- 
tion." Thanks  to  the  labors  of  the  State  Board  of  Health 
of  Massachusetts,  and  to  the  intelligence  of  the  people  of 


238  PURITY   IN   PUBLIC  WATER   SUPPLIES 

that  State  who  have  supplied  the  necessary  funds  to  carry 
on  what  was  perhaps  the  most  elaborate  and  costly  series  of 
experiments  hitherto  undertaken  in  the  interests  of  sanitary 
science,  we  are  to-day  in  full  possession  of  the  data  which 
enable  us  to  define  with  certainty  the  natural  laws  govern- 
ing the  artificial  purification  of  surface  waters  by  simple 
sand  filtration.  These  are  now  a  matter  of  common  knowl- 
edge among  experts,  and  therefore  need  not  be  dwelt  upon 
at  length  at  this  point.  Stated  in  a  few  words,  we  may 
say  that  the  process  of  purification  by  "  natural  filtration  " 
is  accomplished  precisely  as  is  the  case  with  the  rain  fall- 
ing on  porous  earth  (p.  226). 

Land  of  porous  texture  is  first  prepared,  sand  having 
been  found  preferable  for  the  purpose,  while  in  the  best 
practice  specially  constructed  "areas"  or  "beds"  of  sand 
are  made  and  then  thoroughly  underdrained,  so  as  to  facili- 
tate the  collection  of  the  purified  water.  The  water  to  be 
filtered  is  allowed  to  run  over  the  surface  and  find  its  way 
down  through  the  open,  porous  sand.  Very  soon,  however, 
bacteria  take  up  their  residence  on  the  sand  grains,  especially 
near  the  top,  bacterial  jelly  accumulates,  and  a  purifying 
mechanism  or  organism  of  great  efficiency  results.  If  this 
mechanism  be  operated  intermittently,  air  passes  into  the 
interstices  of  the  sand,  precisely  as  into  ordinary  earth, 
only  more  freely;  and  some  of  the  organic  matters  are 
removed  by  nitrification,  that  is,  by  complete  conversion 
into  mineral  matter.  In  this  case,  also,  the  bacterial  jelly 
forms,  but  farther  down  in  the  sand,  and  makes  an  effective 
purifying  medium. 

Innumerable  tests  of  such  mechanisms  as  this  have  been 
made  and  their  high  efficiency  shown.  They  are  usually 
called  sand  "filters,"  but  the  name  is  unfortunate  as  imply- 
ing something  artificial  rather  than  natural.  The  process 
is,  in  fact,  nearly  if  not  exactly  the  same  as  in  the  purifying 
of  surface  waters  which  pass  through  earth  and  become 
ground  waters;  although  by  selecting  the  porous  materials, 


PURIFICATION   BY  MECHANICAL  FILTRATION     239 

"hardness"  and  some  other  faults  of  ground  water  are 
avoided.  It  is  by  such  means  that  London,  Hamburg, 
Berlin,  and  Lawrence  in  Massachusetts,  secure  from  pol- 
luted surface  waters  satisfactory  and  sanitary  supplies. 
Albany  has  followed  in  their  footsteps,  and  Washington, 
Philadelphia  and  many  other  American  cities  must  prob- 
ably do  likewise.  For  the  establishment  of  purity  in  sur- 
face waters,  we  have,  then,  two  important  and  natural 
processes,  —  "storage"  and  "sand  nitration." 


§  13. — Artificial  Processes  of  Purification  of  Water  Supplies 

Various  attempts  have  been  made  to  substitute  artificial 
for  natural  processes  of  purification  of  water  supplies,  and, 
under  certain  circumstances,  there  can  be  no  question  of 
the  importance  or  value  of  these  procedures.  The  only 
processes  of  this  character  thus  far  seriously  proposed  are 
those  known  in  America  as  processes  of  "  mechanical " 
filtration,  for  which  the  advantages  are  claimed  of,  first, 
rapidity ;  second,  hygienic  efficiency ;  third,  removal  of 
clayey  turbidities  and  thorough  decolorization ;  fourth,  con- 
venience of  installation ;  fifth,  cheapness.  The  principles 
involved  in  mechanical  filtration  are  comparatively  simple, 
being  substantially  as  follows :  a  chemical  reagent  of  pre- 
sumably harmless  character,  such  as  alumina,  is  added  in 
a  certain  small  proportion  to  the  water  to  be  purified,  yet 
sufficient  to  produce,  if  the  reaction  of  the  water  be  right, 
a  flocculent  precipitate.  If  the  water  were  kept  quiet  and 
allowed  to  stand,  this  precipitate  would  entangle  and  carry 
to  the  bottom  a  large  amount  of  the  suspended  matters 
present,  including  the  bacteria.  In  fact,  however,  this  is  not 
found  to  be  necessary,  but  after  the  addition  of  the  coagu- 
lant the  water  is  rapidly  passed  through  a  sand  filter  upon 
the  surface  of  which  the  flocculent  precipitate  mentioned 
quickly  collects  and  forms  a  layer.  This  more  or  less  ef- 
fectually detains  suspended  matters,  including  the  bacte- 


240  PURITY   IN   PUBLIC  WATER   SUPPLIES 

ria,  and  removes  from  the  water  a  large  amount  of  any 
color  which  it  may  contain.  Mechanical  appliances,  such 
as  the  reversal  of  the  stream,  allow  for  the  washing  of  the 
sand  filters  and  for  the  repetition  of  the  process,  which 
may  obviously  be  carried  on  rapidly  and  therefore  upon  a 
comparatively  small  area. 

§  14.  —  Hygienic  Efficiency  of  Rapid  Mechanical  Filters 

Tests  of  the  hygienic  efficiency  of  rapid  mechanical  fil- 
ters were  formerly,  for  the  most  part,  wanting,  but  experi- 
ments made  on  the  water  of  the  Ohio  River  at  Louisville, 
Ky.,  and  Cincinnati,  O.,  and  upon  one  of  its  tributaries, 
the  Allegheny  River  at  Pittsburgh,  Penn.,  have  shed  much 
light  upon  the  subject.1 

§  15.  —  Conservation  of  Purity  in  Surface   Waters 

Enough  has  been  said  to  show  that  the  natural  establish- 
ment of  purity  in  water  supplies  is  a  process  somewhat 
elaborate  and  complicated.  The  conservation  of  the  purity 
of  ground  waters,  when  once  they  have  been  collected, 
has  already  been  shown  to  be  a  matter  requiring  intelli- 
gent supervision  (p.  229).  The  same  thing  is  equally  true 
of  surface  waters,  especially  those  required  for  great  cities. 
If,  after  collection,  these  waters  are  stored  in  huge  reser- 
voirs rich  in  organic  matter  (as  is  usually  the  case),  they 
not  infrequently  become  infested  with  microscopical  organ- 
isms which  generate  in  them  disagreeable,  and  sometimes 
even  nauseous,  tastes  and  odors,  of  which  the  consumers 
bitterly  and  very  properly  complain.  The  supply  of  New 

1  Reports  have  appeared  upon  all  of  these  experiments,  namely,  upon  the 
purification  of  the  Ohio  River  at  Louisville  and  at  Cincinnati,  by  George  W. 
Fuller,  on  behalf  of  the  Water  Departments  of  these  cities,  respectively,  and 
at  Pittsburgh  by  Allen  Hazen  on  behalf  of  the  Filtration  Commission  of  the 
city  of  Pittsburgh.  Those  interested  in  the  details  of  this  subject  are  referred 
to  these  reports. 


PURIFICATION   OF   RESERVOIRS   BY   "STRIPPING"     241 

York  City  is  collected  from  watersheds  by  no  means 
uninhabited,  and  is  in  many  respects  well  purified  by 
storage.  Until  very  recently,  however,  it  has  not  been 
thought  necessary,  even  if  it  is  to-day,  in  New  York,  to 
remove  all  possible  organic  matter  from  the  storage  basins 
or  reservoirs  employed. 

The  latest  and  best  practice,  however,  is  exemplified  by 
the  great  Metropolitan  supply  for  Boston  and  the  twenty- 
eight  cities  and  towns  in  its  immediate  vicinity.  There 
the  large  Wachusett  reservoir,  which  alone  is  to  cost 
$9,000,000,  is  now  (in  1901)  being  carefully  prepared,  by 
the  removal  of  all  peat,  muck,  stumps,  loam,  and  other 
organic  matter,  from  the  sides  and  bottom  of  the  reservoir, 
in  order  that  organic  matters  may  be  lacking  for  the  sup- 
port of  these  same  microscopical  organisms  during  storage. 
For  this  specific  purpose  of  "  stripping,"  as  it  is  called,  it 
is  estimated  that  $3,500,000  will  be  spent.  In  this  case, 
which  probably  represents  the  most  advanced  ideas  in  the 
establishment  and  conservation  of  purity  in  surface  waters, 
great  pains  are  being  taken  :  — 

ist.    To  secure  water  originally  of  high  organic  purity. 

2d.   To  keep  the  watersheds  as  uninhabited  as  possible. 

3d.  To  purify  the  water  collected,  by  long  storage  in  an 
immense  reservoir ;  and, 

4th.  To  conserve  its  purity,  when  this  has  once  been 
established,  by  having  the  reservoir  at  the  start  as  free  as 
possible  from  organic  matters  which  might  support  bacteria 
or  microscopical  organisms. 

§  1 6. — Recapitulation 

We  may  point  out  briefly,  in  review,  the  practical  appli- 
cation of  the  principles  now  laid  down,  to  the  water  sup- 
plies of  great  cities,  which,  as  has  been  shown,  must,  for 
the  most  part,  be  surface  waters.  The  aerial  pollutions,  if 
any,  may  be  neglected,  because  beyond  our  control.  But 


242  PURITY   IN  PUBLIC   WATER   SUPPLIES 

with  the  principal  source  of  pollution,  the  watershed,  it  is 
quite  otherwise.  Obviously  the  watershed  largely  deter- 
mines the  character  of  the  surface  water.  The  water- 
shed may  be  uninhabited,  or  thickly  or  thinly  inhabited. 
It  may  consist  of  swampy,  peaty  or  manured  soils ;  or 
of  forests,  rocks  and  barren  slopes ;  or  of  a  combina- 
tion of  such  things ;  and  upon  these  conditions  will 
depend  largely  the  character,  purity  and  conservation 
capacity  of  the  water  collected.  It  is  rarely  the  case 
that  a  great  city  can  secure  for  its  water  supply  a  totally 
uninhabited  watershed,  or  one  free  from  swamps  or  other 
accumulations  of  organic  matter.  Where  a  choice  is  pos- 
sible, it  should  as  far  as  practicable  do  this.  In  the  ideal 
system  of  surface-water  supply,  the  city  should  own  the 
entire  watershed,  and  keep  it  clean  and  uninhabited.  But 
if,  as  will  usually  be  the  case,  the  watershed  is  more 
or  less  inhabited  and  swampy,  pains  must  be  taken  to 
guard  against  specific  pollutions  from  habitations,  and  to 
drain  swamps,  so  as  to  collect  the  rainfall  from  the  for- 
mer as  slowly,  and  from  the  latter  as  quickly,  as  possible. 
For  all  the  details  of  these  matters,  the  most  intelligent 
and  educated  sanitary  supervision  are  required.  This  is 
the  place  for  young  sanitary  engineers  who,  as  careful 
scientific  inspectors,  should  be  employed,  not  occasionally 
or  spasmodically,  but  regularly  and  permanently,  to  guard 
the  sanitary  condition  of  watersheds.  To  bring  about 
even  the  possibility  of  this,  special  legislation  may  be 
necessary,  as  for  example  was  found  to  be  the  case  in 
Massachusetts,  where  formerly  the  law  did  not  allow  any 
city  or  town,  or  any  sanitary  authority  on  their  complaint, 
to  abate  nuisances  or  remove  sources  of  pollution  upon 
any  part  of  the  watershed  from  which  it  derived  its  drink- 
ing water.  Afterward  a  statute  was  enacted,  making  it 
possible,  by  due  process  of  law,  for  the  State  Board  of 
Health  (on  complaint)  to  remove  sources  of  pollution 
"  within  the  distance  of  one  hundred  feet  of  the  high-water 


INTELLIGENT  SUPERVISION   INDISPENSABLE      243 

mark  of  any  stream  or  pond,  or  any  stream,  pond,  spring, 
or  water-course  tributary  thereto,  polluting  or  tending  to 
pollute  such  stream,  pond,  spring,  or  water-course." 

§  17. — Protection  of  Purity  of  Inland  Waters  in 
Massachusetts 

The  progress  of  legislation  toward  the  better  control,  or 
sanitary  protection,  of  watersheds  is  interesting  and  instruc- 
tive, as  it  is  laid  down,  for  example,  in  the  Massachusetts 
statutes.1 

Previous  to  1878  there  was  apparently  in  Massachusetts 
no  attempt  to  guard  against  pollution  of  public  water 
supplies,  still  less  of  the  watersheds  from  which  they 
were  derived;  but  in  that  year  it  was  made  illegal  to 
discharge  into  any  stream  or  pond  used  as  a  source  of 
water  supply  polluting  material  within  twenty  miles  above 
the  point  where  the  supply  was  taken.  We  see  here  em- 
bodied in  legislation  the  influence  of  the  old  theory  of 
"self-purification"  —twenty  miles  having  been  formerly 
regarded  as  an  ample  distance  within  which  a  stream 
might  purify  itself. 

In  1879  it  was  made  illegal  to  deposit  excrement  or  foul 
or  decaying  matter  in  any  water  used  for  domestic  water 
supply  on  or  upon  the  shore  thereof  within  five  rods  of 
the  water ;  but  it  was  also  specially  provided  that  this  act 
should  not  be  construed  to  interfere  with  the  putting  in  of 
the  sewage  of  a  city,  town  or  public  institution,  or  to 
prevent  boating,  bathing  or  fishing,  or  the  enriching  of 
land  for  agricultural  purposes. 

It  was  not  until  1890  that  any  legislation  of  a  thoroughly 
modern  sort,  in  harmony  with  the  sanitary  science  of  the 
day,  was  enacted,  and  this  was  of  the  limited  description 

1  The  English  Public  Health  Act  of  1875  took  very  advanced  ground  on 
this  subject,  and  was  doubtless  the  model  after  which  much  of  the  Massa- 
chusetts law  was  shaped. 


244  PURITY  IN  PUBLIC  WATER  SUPPLIES 

already  referred  to,  inasmuch  as  it  restricted  the  powers 
of  the  State  Board  of  Health,  as  a  sanitary  authority  to  be 
appealed  to,  to  the  limit  of  one  hundred  feet  from  the  high- 
water  mark  of  any  stream  or  pond,  or  any  tributary  of  the 
same.  This  was,  of  course,  a  distinct  advance ;  but  with 
the  inauguration  of  the  Metropolitan  Water  Supply  for 
Boston  and  vicinity,  special  legislation  was  secured  for  that 
area,  which  provided  absolute  control  by  the  State  Board  of 
Health  over  the  sanitary  condition  of  the  entire  watersheds 
which  it  was  proposed  to  use. 

§  1 8.  —  Sanitary  Protection  of  Public    Water  Supplies 

In  Chapter  488  of  the  Acts  of  the  General  Assembly  of 
Massachusetts  for  the  year  1895,  to  provide  for  a  Metro- 
politan Water  Supply,  an  advanced  position  was  taken  in 
regard  to  the  sanitary  protection  of  water  in  Massachusetts 
in  the  following  sections :  — 

SANITARY  PROTECTION   OF  WATER 

SECTION  24.  The  State  Board  of  Health  is  hereby  authorized  and 
required  to  make  rules  and  regulations  for  the  sanitary  protection  of  all 
waters  used  by  the  Metropolitan  Water  Board  for  the  water  supply  of 
any  city,  town,  or  water  company  aforesaid.  .  .  . 

ENFORCEMENT 

SECTION  27.  Said  Metropolitan  Water  Board  and  their  employees 
designated  for  the  purpose  shall  enforce  the  provisions  of  this  act,  and 
of  the  rules,  regulations,  and  orders  made  thereunder,  and  may  enter  into 
any  building,  and  upon  any  land,  for  the  purpose  of  ascertaining  whether 
sources  of  pollution  there  exist,  and  whether  the  provisions  of  this  act 
and  of  the  rules,  regulations,  and  orders  made  as  aforesaid  are  complied 
with.  .  .  . 

In  1897  what  was  practically  the  same  authority  was 
granted  to  the  State  Board  of  Health,  covering  all  water- 
sheds within  the  state  of  Massachusetts  tributary  to  public 
water  supplies,  in  the  shape  of  an  act,  Chapter  510,  Acts  of 


PROTECTION   OF   PURITY   BY   LEGISLATION        245 

1897,  which  reads  as  follows,  and  probably  represents,  as 
nearly  as  can  be  expected  in  conservative  legislation,  the 
best  ideas  of  the  sanitary  science  of  to-day  on  this  subject. 


ACTS   OF    1897.     CHAPTER   510 
An  Act  relative  to  the  Pollution  of  Sources  of  Water  Supply 

Be  it  enacted,  etc.,  as  follows :  — 

SECTION  i.  The  State  Board  of  Health  shall  have  the  general 
supervision  of,  and  have  authority,  from  time  to  time,  as  it  may  deem 
expedient,  to  examine  all  streams  and  ponds  used  by  any  city,  town,  or 
water  or  ice  company  in  this  Commonwealth  as  sources  of  water  supply, 
together  with  all  springs,  streams,  and  water  sources  tributary  thereto, 
with  reference  to  their  purity,  and  shall  have  authority  to  make  rules, 
regulations,  and  orders  for  the  purpose  of  preventing  the  pollution,  and 
securing  the  sanitary  protection  of  the  same. 

SECTION  2.  Said  Board  shall  appoint  such  agents  and  servants  as 
it  may  deem  necessary,  who  shall  attend  to  the  enforcement  of  the  pro- 
visions of  this  act  and  of  the  rules,  regulations,  and  orders  thereunder, 
and  shall  hawe  the  power,  by  such  agents  and  servants  as  aforesaid,  to 
enter  into  and  upon  any  building  structure  and  premises  for  the  purpose 
of  ascertaining  whether  or  not  any  sources  of  pollution  or  danger  to  the 
water  supply  there  exist,  and  whether  or  not  the  provisions  of  this  act 
and  the  rules,  regulations,  and  orders  made  as  aforesaid  are  complied 
with  and  obeyed.  .  .  . 

SECTION  3.  Upon  complaint  to  said  State  Board  of  Health  by  the 
mayor  of  a  city  or  the  selectmen  of  a  town,  or  by  a  board  of  water  com- 
missioners, or  by  the  president  of  a  water  or  ice  company,  that  manure, 
excrement,  garbage,  sewage,  or  any  other  matter  is  so  deposited,  kept  or 
discharged  as  to  pollute  or  tend  to  pollute  the  waters  of  any  stream, 
pond,  spring,  or  water-course  used  by  a  city,  town,  water  or  ice  company 
as  a  source  of  water  supply,  or  that  any  other  cause  of  pollution  to  such 
water  supplies  exists,  the  said  Board  of  Health  shall  appoint  a  time  and 
place  for  hearing  parties  to  be  affected,  and  give  due  notice  thereof  to 
such  parties;  and  after  such  hearing,  if  in  its  judgment  the  public 
health  requires  it,  shall  prohibit  the  deposit,  keeping,  or  discharge  of 
any  such  material,  or  other  cause  of  pollution  as  aforesaid,  and  shall 
order  any  person  to  desist  therefrom  and  to  remove  any  such  material 
theretofore  deposited,  or  other  cause  of  pollution ;  but  said  Board  shall 
not  prohibit  the  cultivation  and  use  of  the  soil  in  the  ordinary  methods 


246  PURITY  IN  PUBLIC  WATER  SUPPLIES 

of  agriculture,  provided  that  no  human  excrement  is  used  thereon.  But 
said  Board  shall  not  prohibit  the  use  of  any  structure  which  was  in 
existence  at  the  time  of  the  passage  of  this  act,  in  case  the  complaint 
referring  to  or  including  such  structure  is  made  by  the  board  of  water 
commissioners  of  any  city  or  town,  or  by  any  water  or  ice  company, 
unless  the  board  of  water  commissioners  or  the  water  or  ice  company 
making  the  complaint  shall  file  with  the  said  State  Board  of  Health  an 
order  or  vote  of  its  city  council,  selectmen,  or  water  or  ice  company 
respectively,  to  the  effect  that  such  city,  town,  or  water  or  ice  com- 
pany will,  at  its  own  expense,  make  such  changes  in  said  structure  or 
its  location  as  said  Board  shall  deem  expedient.  Such  order  or  vote 
shall  be  binding  on  such  city,  town,  or  water  or  ice  company  ;  and, 
when  such  changes  shall  have  been  made,  all  damages  occasioned 
thereby  shall  be  paid  by  such  city,  town,  or  water  or  ice  company ;  and 
if  the  parties  cannot  agree  thereon,  such  damages  shall  be  determined 
by  a  jury  on  petition  of  either  party,  filed  in  the  clerk's  office  of  the 
superior  court  in  the  county  where  the  premises  are  located,  in  the 
manner  provided  by  law  in  relation  to  determining  the  damages  occa- 
sioned by  taking  land  for  highways  in  such  city  or  town,  or  in  the  case 
of  a  water  or  ice  company,  in  the  city  or  town  in  which  the  said  struc- 
ture is  located.  .  .  . 

SECTION  6.  Whoever  does  any  of  the  acts  herein  prohibited  or 
violates  or  refuses  to  comply  with  any  rule,  regulation,  or  order  made 
under  the  authority  of  this  act  shall  be  punished  for  each  offence  by  a 
fine  not  exceeding  five  hundred  dollars,  to  be  paid  to  the  Commonwealth, 
or  by  imprisonment  not  exceeding  one  year  in  the  House  of  Correction, 
or  by  both  such  fine  and  imprisonment. 

This  law  was  secured  only  after  it  had  been  found  that, 
under  previous  legislation  which  had  established  a  hun- 
dred-foot limit,  it  was  quite  impossible  adequately  to  protect 
Massachusetts  watersheds  from  pollution. 


§  19.  —  Sanitary  Protection  and  Inspection  of  Watersheds 

Of  late  years  it  has  been  also  learned,  at  least  in  Mas- 
sachusetts, that  serious  pollutions,  similar  to  that  which 
affected  the  ground-water  supply  of  Caterham,  England 
(p.  191),  may  occur  in  surface  supplies  from  the  temporary 
residence  on  the  watershed  of  thousands  of  laborers,  some 
of  whom  may  be  walking  cases  of  infectious  disease.  Two 


SANITARY  PROTECTION   OF  WATERSHEDS        247 

examples  of  this  kind  have  occurred  within  the  author's 
experience. 

The  first  happened  in  1894,  while  a  new  reservoir  of 
great  size  was  under  construction  for  a  large  and  important 
American  city.  When  finished  it  was  to  be  connected  with 
and  added  to  an  existing  system  of  reservoirs,  and  during 
the  work  of  stripping  off  the  loam  and  building  the  dam 
large  gangs  of  men  were,  of  necessity,  employed.  The 
stream  which  was  to  be  dammed  naturally  ran  through  the 
valley  where  these  men  worked,  and  on  into  the  lower 
reservoirs,  constituting  the  then  existing  supply  of  the  city. 

An  epidemic  of  typhoid  fever  broke  out  among  the  labor- 
ers. The  author  was  called  in  to  study  the  cause  of  the 
typhoid  fever,  but  very  soon  saw  that,  valuable  as  such 
study  might  be  from  the  aetiological  point  of  view,  the 
possible  effects  of  the  epidemic  were  practically  far  more 
important  and  pressing.  He  was  sent  to  find  the  cause  of 
the  typhoid  fever ;  but  this  question  had  to  wait,  as  soon 
as  he  saw  the  true  state  of  affairs,  while  he  tried  to  prevent 
the  typhoid  germs  produced  by  the  people  who  were  work- 
ing on  the  brook,  and  using  it  as  their  sewer,  from  reaching 
the  consumers  of  the  water  below.  There  were  hundreds 
of  men  at  work,  and  a  large  number  of  them  were  suffering 
with  typhoid  fever.  All  were  living  or  working  about  or 
very  near  the  brook.  Many  were  visibly  using  it  as  a  drain 
and  a  defecating  place,  and  were  defiling  its  shores  at 
various  points  from  which  material  during  a  sudden  shower 
was  readily  washed  into  the  brook  and  conveyed  to  a  reser- 
voir below.  Fortunately  the  system  of  reservoirs  allowed 
this  one  to  be  disconnected  for  a  time.  The  purifying 
effects  of  quiescence  and  storage  were  called  in.  The 
watershed  was  cleaned  up,  disinfection  was  employed,  and 
every  possible  precaution  taken  to  prevent  further  trouble. 
It  is  pleasant  to  be  able  to  record  the  fact  that  the  efforts 
of  those  concerned  were  entirely  successful. 

The  other  case  was  very  similar.     Another  large  city  was 


248  PURITY   IN   PUBLIC  WATER   SUPPLIES 

building  a  huge  storage  reservoir.  Two  thousand  laborers 
were  employed  and  lived  upon  the  watershed,  close  to  the 
stream  which  was  to  be  dammed  up.  Typhoid  fever  broke 
out  among  them.  They  were  very  ignorant,  and  even  when 
closely  watched  persisted  in  washing  their  soiled  clothing  in 
the  brook  which  ran  down  into  the  city  supply  below.  Ex- 
traordinary pains  had  to  be  taken  to  make  sure  that  the 
purity  of  this  infected  supply  was  reestablished  and  con- 
served before  it  was  delivered  to  the  consumers.  The  chief 
responsibility  in  this  case,  also,  fell  upon  the  author,  who 
was  fortunately  successful  in  his  efforts  to  prevent  infec- 
tion from  reaching  the  users  of  the  water. 

Still  another  lately  recognized  source  of  pollution  of 
watersheds  is  their  use  for  picnic  purposes  and  summer 
resorts.  In  1896  the  attention  of  the  State  Board  of 
Health  of  Massachusetts  was  called  to  this  subject,  and 
the  author  had  the  privilege  of  supervising  a  general  in- 
vestigation of  the  sanitary  condition  of  all  the  picnic  and 
summer  resorts  of  the  state,  but  especially  those  located 
on  the  watersheds  of  public  water  supplies,  with  a  view  to 
learning  the  character  and  extent  of  the  pollutions,  if  any. 
The  results  showed  that  in  many  cases  dangerous  pollutions 
existed  upon  the  watersheds,  seriously  imperilling  the  pu- 
rity of  the  supplies  with  which  they  were  connected.  In  the 
following  year  the  work  was  repeated,  with  equally  satis- 
factory results.  The  development  of  electric  street  railway 
systems  has,  in  Massachusetts  at  least,  caused  many  new 
"resorts"  to  spring  up  in  out-of-the-way  places  (often 
chosen  largely  because  of  their  isolation  and  wildness), 
and  in  not  a  few  cases  on  or  near  lakes  and  reservoirs  used 
for  water  supplies,  or  upon  their  watersheds. 

Far  more  serious,  of  course,  are  those  instances  in  which 
villages  or  towns  are  situated  within  or  upon  a  watershed. 
These  cases  often  require  the  most  careful  study  and  super- 
vision. Sometimes  it  is  necessary  and  possible  to  divert 
their  drainage  from  the  watershed ;  sometimes,  when  this  is 


SANITARY   SUPERVISION  OF  WATERSHEDS       249 

impracticable,  it  can  be  purified  on  a  sewage  farm  within 
the  watershed ;  sometimes  other  procedures  are  required. 
Here  again  intelligent  supervision  and  control  are  required, 
which  must  be  permanent,  inasmuch  as  the  conditions  on 
the  watershed  are  subject  to  frequent  and  often  unexpected 
change.  Few  American  cities,  if  any,  have  to-day  such 
supervision  as  the  standards  of  modern  science  demand.  It 
is  not  enough  to  burn  occasionally  a  few  barns  or  to  pur- 
chase and  remove  a  few  pig-pens  on  the  watershed.  The 
problem  is  larger  than  this,  and  requires  thoughtful,  en- 
lightened and  continuous  public  service  for  its  proper 
amelioration. 

After  the  careful  collection  of  the  water  from  the  water- 
shed, it  should  be  subjected  to  one  or  the  other,  or  both,  of 
the  two  great  methods  of  natural  purification  —  storage 
or  filtration  —  in  order  to  correct  whatever  defects  it  may 
still  possess.  If  it  be  a  ground  water,  further  filtration  is 
generally  needless,  but  its  storage  must  be  effected  in  the 
absence  of  light.  If  it  be  a  surface  water,  it  should  without 
question  be  stored  for  a  time  and,  when  possible,  in  well- 
stripped  reservoirs,  i.e.  in  reservoirs  freed  from  organic 
matters. 

A  wise  writer,  it  will  be  remembered,  has  recommended 
"  old  books  to  read,  old  wine  to  drink,  old  wood  to  burn." 
It  has  since  been  discovered,  in  addition,  that  old  water  is 
better  than  new.  It  is  said  that  the  old-time  sea  captains 
seldom  allowed  any  water  to  be  used  on  board  ship  that 
had  not  been  in  the  casks  for  months.  The  theory  was 
that  water,  like  wine,  underwent  a  "working"  or  fermenta- 
tion which  improved  its  salubrity.  We  now  know  that 
they  were  right,  and,  better,  we  know  why :  it  was  simply 
that  harmful  bacteria  were  given  ample  time  to  die  out. 

If  a  surface  water  is  known  to  be  much  polluted  when 
collected,  the  more  difficult  and  more  heroic  treatment  of 
filtration  should  be  invoked.  Here  again,  in  any  particular 
case,  experience  and  judgment  are  required.  London 


250  PURITY   IN    PUBLIC  WATER   SUPPLIES 

first  stores  and  then  niters,  with  excellent  results.  Ham- 
burg does  the  reverse,  and  so  does  Lawrence,  and  when 
practicable,  storage,  both  before  and  after  nitration,  is 
probably  desirable  and  useful. 

§  20.  —  Expert  Supervision  an  Absolute  Requirement 
of  Modern  Sanitation 

The  keynote  of  public  service  is  expert  supervision. 
With  this  remark  we  return  to  the  point  from  which  we 
started.  If  a  public  supply  is  to  be  made  a  public  bless- 
ing, it  must  be  scientifically  and  skilfully,  as  well  as  eco- 
nomically, administered.  It  will  not  do  to  leave  to  the 
shifty  devices  of  petty  politicians  matters  like  water  sup- 
ply, gas  supply,  and  food  supply,  which  require,  for  mere 
public  safety,  skilled  anid  highly  paid  supervision.  If 
democratic  government  is  to  endure  and  to  exemplify  a 
form  of  civilization  above  that  of  the  republics  of  Central 
America,  in  which  plunder  and  bad  government  are  the 
rule,  the  people  must  see  to  it  that  in  the  place  of  small 
politicians  to  manage  these  things,  they  have  educated  pub- 
lic servants ;  instead  of  neglecting  to  care  for  watersheds, 
these  must  be  supervised  by  men  technically  trained ;  and 
instead  of  bosses  and  heelers  to  deal  with  these  problems 
in  their  larger  aspects,  there  must  be  faithful  and  able 
experts.  Only  on  this  condition  can  we  afford  to  surrender 
private  supervision  of  some  of  the  principal  avenues  of  our 
well-being  for  public  supervision  ;  and  until  the  most  expert 
public  supervision  attainable  takes  the  place  of  private 
control,  it  will  remain  true  that  a  public  supply  is  a  public 
danger.  (Cf.  p.  221.) 


CHAPTER   X 

ON   ICE   AS   A   VEHICLE   OF   INFECTIOUS   DISEASE.      THE   POL- 
LUTION OF  ICE.     ICE  SUPPLY  AND  THE  PUBLIC  HEALTH  1 

§  I.  —  The  Mingling  of  Melted  Ice  with  Food' and  Drink 

THE  almost  universal  American  custom  (now  rapidly 
spreading  in  Europe)  of  cooling  certain  drinks  —  such  as 
water,  lemonade  and  tea  —  by  adding  to  them  lumps  of  ice, 
which  are  allowed  to  melt  and  mingle  with  liquid  to  be 
swallowed,  early  attracted  the  attention  of  sanitarians,  to 
whom  the  idea  naturally  occurred  that  if  the  ice  thus  added 
be  impure,  serious  consequences  may  result.  The  amount  of 
ice  consumed  in  this  way  in  America  alone  during  the  warm 
season,  and  indeed  all  the  year  round,  is  simply  enormous. 
It  is  the  almost  invariable  rule  in  hotels  and  restaurants 
to  begin  the  service  of  a  guest  at  table  by  filling  his  glass 
with  broken  pieces  of  ice  or  "  cracked "  ice,  and  at  least 
one  observer  of  American  life  and  manners  ha~  cleverly 
commented  upon  this  almost  national  habit.2  In  some 
clubs  and  hotels  drinking  water  is  put  upon  the  table 
in  the  shape  of  glass  water-bottles  (carafes),  in  which  the 
water  has  been  frozen  j  solid,  filling  the  bottle  with  one 
solid  mass  of  ice.  This  gradually  melts  during  the  meal, 
and  the  water  which  is  poured  from  it  for  drinking  in  this 

1  This  subject  is  treated  at  much  length,  and  with  full  references  to  the  litera- 
ture, in  a  paper  by  the  author  and  C.-E.  A.  Winslow,  S.  M.,  recently  published 
in  the  Memoirs  of  the  American  Academy  of  Arts  and  Sciences  in  Boston,  Vol. 
XII,  No.  V.     Frequent  extracts  from  this  paper  are  made  in  the  present  chapter. 

2  ..."  Ice-water,  the   musical  tinkling  of  which  in  the  corridors  is  the 
most  characteristic  sound  of  the  American  caravanserai."  —  J.  F.  MUIRHEAD, 
"The  Land  of  Contrasts,"  Boston,  1898. 

251 


2$2     ICE   AS   A  VEHICLE   OF   INFECTIOUS   DISEASE 

case  comes  wholly  from  melted  ice.  Pleasure  parties,  ex- 
cursion parties,  and  the  like  often  make  use  of  large  tubs 
of  drink  (water,  lemonade,  etc.),  into  which  a  cake  of  ice  is 
put  bodily ;  and  this,  in  melting,  not  only  cools  the  sur- 
rounding liquid,  but  contributes  to  it  whatever  impurities  it 
may  contain.  Raw  oysters  (removed  from  the  shell)  are 
sometimes  placed  upon  a  luncheon  or  dinner  table  in  a 
cubical  cavity,  cut  into  the  top  of  a  large  block  of  ice,  and 
are  later  served  with  more  or  less  of  the  meltings  of  the 
sides  and  bottom  of  the  ice-cavity  in  which  they  lie.  It  is 
plain  that  if  the  germs  of  infectious  disease  or  other  impu- 
rities can  survive  in  ice,  this  when  melted  may  form  a  ready 
vehicle  for  the  distribution  of  disease. 

§  2. — Does  Polluted  Water  purify  itself  in  Freezing? 

It  is  a  popular  belief  that,  at  least  in  many  cases,  the  ice 
which  forms  upon  a  body  of  water  is  purer  than  the  water 
itself.  This  belief  is  probably  based  in  part  upon  the  well- 
known  fact  that  when  a  substance  crystallizes  out  of  a 
liquid  the  crystals  formed  are  usually  purer  than  the 
mother-liquor  from  which  they  come ;  and  general  reliance 
seems  to  have  been  placed  (in  America)  upon  this  tendency 
to  purification  to  which  ice  crystals  also  might  be  expected 
to  be  subject,  until,  in  1887,  careful  investigations  by  Prud- 
den  showed  that  bacteria  are  not  wholly  eliminated  from 
ice  in  the  freezing  of  water,  and  that  these  may  even  sur- 
vive in  ice  for  long  periods.  It  was  then  remarked  that 
ice  often  contains  visible  impurities,  and  if  these,  why  not 
also  others  invisible  ? 

A  little  reflection  will  show  that  the  question  of  elimina- 
tion of  impurities  such  as  bacteria,  which  are  really  sus- 
pended particles,  depends  for  its  solution  upon  a  variety  of 
conditions.  If,  for  example,  the  body  of  water,  e.g.  a  small 
lake  or  pond,  containing  bacteria  be  frozen  absolutely  solid, 
as  in  the  case  of  the  carafes  of  drinking  water  mentioned 


PARTIAL   PURIFICATION   OF  WATER  BY   FREEZING     253 

above,  there  is  no  reason  to  expect  elimination  during  crys- 
tallization, for  there  is  no  place  into  which  the  bacteria  can 
be  extruded  by  the  growing  crystals.  But  if  the  ice  in 
question  is  formed  on  the  surface  of  a  quiet  lake  or  pond, 
the  very  first  skimming  of  crystals  produces  absolute  quies- 
cence in  the  underlying  layers  of  water,  and  gravity  must 
then  exert  a  powerful  effect  upon  the  floating  bacteria. 
In  this  case  there  is  abundant  opportunity  for  the  elimina- 
tion of  foreign  particles  by  the  growing  crystals;  and  as 
these  gradually  extend  downward,  they  will  naturally  first 
invade  those  layers  of  water  nearest  to  themselves,  which, 
for  obvious  reasons,  may  be  the  freest  from  bacteria,  while 
the  lower  layers  of  the  pond  will  contain  not  only  the  bac- 
teria belonging  to  themselves,  but  also  such  as  have  been 
dragged  down  by  gravity  from  the  upper  layers.  Accord- 
ingly, the  uppermost  layer  of  such  ice  will  often  be  the 
richest  in  bacteria ;  while  the  next  lower  ice  layers,  espe- 
cially if  their  formation  has  been  slow,  may  be  relatively 
free  from  bacteria. 

Again,  to  take  another  case :  If,  as  is  often  done,  the  har- 
vesters, after  a  few  inches  of  ice  have  been  formed,  cut 
holes  in  the  ice-sheet,  allowing  the  subnatant  water  to  over- 
flow it,  and  by  freezing  solidly  from  above  to  become  added 
bodily  to  that  already  formed,  the  conditions  in  the  case 
of  this  added  layer  will  be  similar  to  those  in  the  carafe. 
The  mass  will  be  frozen  as  a  whole,  and  no  mechanical 
elimination  during  crystallization  can  reasonably  be  ex- 
pected. Lastly,  if,  after  the  ice  has  begun  to  form,  snow 
falls  upon  it,  and  this,  by  a  rainfall  or  a  thaw  followed  by 
freezing  weather,  becomes  added  as  a  superficial  layer  of 
"  snow-ice "  to  that  upon  which  it  fell,  such  "  snow-ice " 
may  be  expected,  from  what  has  been  said  above  (p.  224) 
in  regard  to  the  action  of  snow  as  an  atmospheric  filter,  to 
contain  large  numbers  of  bacteria. 

From  these  various  considerations  we  may  conclude  that 
the  answer  to  the  question,  Does  water  purify  itself  in 


254     ICE   AS   A  VEHICLE   OF   INFECTIOUS  DISEASE 

freezing  ?  depends  largely  upon  the  conditions  under 
which  it  is  frozen.  If  ice  is  formed  upon  a  quiet  lake 
or  pond  of  considerable  depth,  the  water  of  the  pond 
probably  does  purify  itself  to  a  marked  degree  in  freez- 
ing. But  if,  on  the  other  hand,  the  freezing  takes  place 
in  such  a  way  that  sedimentation  has  little  influence,  or  if 
an  entire  mass  of  water  is  frozen  solid,  purification  may  be 
much  less  marked,  or  even  largely  wanting.1 

§  3. — Epidemics  attributed  to  Infected  Ice 

In  spite  of  the  fact  that  ice  may  contain  very  consider- 
able numbers  of  bacteria,  and  that  it  has  been  hitherto 
regarded  as  a  dangerous  vehicle  of  disease,  only  a  surpris- 
ingly small  number  of  epidemics  have  been  charged  to 
infected  ice ;  and  a  careful  examination  of  the  reports  of 
these  leaves  upon  the  student  the  impression  that  the  dan- 
gers of  polluted  ice  have  probably  been  exaggerated. 

The  first  epidemic  attributed  to  infected  ice,  and  care- 
fully investigated,  occurred  at  a  summer  resort  known  as 
Rye  Beach,  New  Hampshire,  in  1875.  The  illness  in 
question  —  a  severe  intestinal  disorder  —  was  confined  to 
the  guests  of  one  of  the  large  hotels.  The  milk  supply, 
the  water  supply,  and  the  drainage  appeared  to  be  above 
suspicion ;  but  the  ice  supply  had  been  derived  from  a 
small  pond,  the  waters  of  which  were  rendered  very  foul  by 
a  mass  of  putrescent  matter  composed  of  a  mixture  of  marsh 
mud  and  decomposing  sawdust.  Chemical  analysis  of  the 
water  from  the  pond  and  of  the  ice  showed  the  presence 
of  high  total  organic  matter  and  high  ammonias,  both  free 
and  albuminoid.  The  inference  was  that  the  disease  had 
somehow  come  from  the  ice.  In  1878  Dr.  Charles  Smart, 
surgeon  United  States  Army,  attributed  certain  cases  of 

1  See  Thirty-second  Annual  Report  of  the  State  Board  of  Health  of  Massa- 
chusetts for  1900,  pp.  510,  et  seq.  Boston,  1901.  Twenty-first  Report  (for 
1889),  p.  145,  et  seq.  Boston,  1890. 


ILLNESS   CHARGED   TO   IMPURE  ICE  255 

"malarial  remittent"  fever  in  a  Rocky  Mountain  army 
post  to  the  contamination  of  mountain  streams  by  melting 
snow.  In  1879  an  outbreak  of  dysentery  occurred  in  Con- 
necticut in  a  family  of  eleven  persons  residing  in  a  farm- 
house. There  were  in  all  eight  cases  of  disease,  of  which 
three  proved  fatal.  This  epidemic  was  charged  to  ice 
which  had  been  cut  on  a  small  stream  used  as  a  running- 
place  for  pigs.  In  1882  a  single  case  of  typhoid  fever 
charged  to  ice  occurred  in  the  same  state.  The  patient 
lived  otherwise  under  excellent  sanitary  conditions,  but  was 
much  addicted  to  iced  water,  of  which  he  consumed  large 
quantities,  the  ice  having  come  from  a  pond  into  which 
drains  from  some  laborers'  houses  emptied.  In  these 
houses  there  had  been  three  cases  of  typhoid  fever  during 
the  previous  summer.  Excepting  the  Rye  Beach  epidemic 
already  mentioned,  the  most  notable  epidemic  of  disease 
connected  with  frozen  water  (snow)  is  that  of  typhoid  fever 
in  Plymouth,  Penn.,  in  1885  (cf.  pp.  200-206).  In  this  case 
the  epidemic,  which  was  of  very  large  proportions,  was 
clearly  traced  to  the  pollution  of  the  public  water  supply 
by  the  dejecta  of  a  single  patient  suffering  from  typhoid 
fever.  Moreover,  these  dejecta  had  been  thrown,  without 
disinfection,  upon  the  snow  which  covered  the  ground  near 
the  house  in  which  the  patient  lay  ill,  and  had,  in  part  at 
least,  probably  been  thoroughly  frozen.  When  finally  the 
mass  was  melted  by  the  arrival  of  warmer  weather,  and  had 
been  washed  by  rains  into  the  public  water  supply,  a  very 
extensive  and  serious  epidemic  ensued.  It  appears,  how- 
ever, that  while  the  earlier  dejecta  were  thus  almost  certainly 
exposed  to  a  very  low  air  temperature,  the  same  cannot 
be  said  of  the  excreta  thrown  out  just  before  the  "  thaw  " 
occurred ;  so  that  it  is  by  no  means  certain  that  all  were 
exposed  to  a  freezing  temperature.  Besides,  faecal  mat- 
ters frozen  solidly  en  masse  are  very  unlike  ice,  properly 
so  called,  or  such  as  is  used  for  public  ice  supply,  and  the 
former  might  easily  be  a  much  more  favorable  medium  for 


256     ICE   AS   A   VEHICLE   OF   INFECTIOUS   DISEASE 

the  viability  of  microbes  than  the  latter.  Accordingly, 
even  if  we  allow  that  the  Plymouth  epidemic  was  caused 
by  germs  which  had  resisted  very  low  temperatures,  it 
would  not  by  any  means  follow  that  ice  as  ordinarily  made 
and  used  is  an  important  vehicle  of  disease. 

Owing  to  the  hitherto  limited  use  in  Europe  of  ice  for 
cooling  drinks,  we  should  not  expect  to  find  on  record  many 
European  epidemics  charged  to  infected  ice.  The  only  one 
which  need  be  cited  here  occurred  at  the  military  post 
of  Rennes  in  1895.  Eight  lieutenants  of  a  regiment  fell 
ill  of  typhoid  fever  between  December  12  and  25.  The 
fact  that  these  officers  did  not  ordinarily  live  in  common, 
but  had  all  attended  a  regimental  banquet  on  December  4, 
pointed  to  something  taken  at  that  time  as  the  vehicle  of 
infection.  The  officers  of  higher  rank,  among  whom  no 
disease  appeared,  dined  in  a  separate  room  and  used  for 
water  only  the  town  supply,  which  was  excellent.  The 
lieutenants  on  the  other  hand  shared  a  "tisane  "  of  cham- 
pagne which  they  mixed  with  chilled  water.  It  was  sup- 
posed at  first  that  this  water  was  derived  from  the  town 
supply,  but  afterward  that  it  came  from  the  melting  of  the 
ice  used  for  general  refrigeration ;  and  this  ice  was  believed 
to  be  highly  polluted.  The  menu  of  the  various  classes  of 
officers  was  the  same,  and  certain  of  the  petty  officers  who 
did  not  share  the  "tisane,"  but  drank  beer  instead,  were 
not  attacked. 

Reviewing  the  evidence,  it  seems  probable  that  certain 
intestinal  disorders  caused  by  decomposing  organic  mat- 
ters, if  not  by  the  more  well-defined  pathogenic  germs, 
have  at  times  been  caused  by  polluted  ice.  The  Rye 
Beach  epidemic  was  carefully  studied,  and  points  directly 
to  this  conclusion.  On  the  other  hand,  we  have  not  been 
able  to  find  much  satisfactory  evidence  that  typhoid  fever 
or  other  well-known  infectious  diseases  are  carried  in  this 
way  ;  but  the  possibility  that  some  obscure  "  sporadic  "  cases 
are  due  to  infected  ice,  cannot  be  denied. 


ILLNESS   CAUSED   BY  IMPURE   ICE  257 

§  4.  —  Investigations  of  the  Purity  of  Ice  by  Various 
Observers 

As  early  as  1871  Professor  Burdon-Sanderson  observed 
that  (liquid)  culture  media  showed  bacterial  growth  when 
inoculated  with  melted  snow  or  ice.  Von  Frisch  froze 
putrefying  solutions,  subjected  the  frozen  mass  to  a  tem- 
perature of  —  87  °  C.  and  after  the  lapse  of  some  hours 
found  that  sterilization  had  not  been  effected. 

Professor  Joseph  Leidy  in  1884  exhibited  at  a  meeting  of 
the  Academy  of  Natural  Sciences  of  Philadelphia  water  de- 
rived from  melted  ice  containing  not  only  living  infusoria 
but  also  rotifers  and  other  worms.  Pictet  and  Young  sub- 
jected various  species  of  bacteria  to  a  temperature  below 
—  70°  C.  for  108  hours  (during  20  hours  below  —  130°  C.). 
After  this  treatment  the  cultures  of  B.  anthracis  and  the 
bacillus  of  symptomatic  anthrax  were  alive  and  virulent. 
Kowalski  analyzed  60  specimens  of  natural  ice  and  obtained 
from  10  to  1000  colonies  per  cubic  centimetre,  no  specimen 
being  sterile.  Schmelk  studied  the  bacterial  life  in  the  snow 
(and  ice)  of  a  Norwegian  glacier  and  in  the  cold  streams 
flowing  from  it.  Bujwid  found  21,000  bacteria  per  cubic 
centimeter  in  a  melted  hailstone,  and  similar  though 
smaller  figures  have  been  obtained  by  others  (Foutin, 
Abbott).  Heyrothin  1888-1889  obtained  in  the  ice  supply 
of  Berlin  from  2  to  133,000  bacteria  per  cubic  centimetre, 
the  highest  figures  corresponding  to  chemical  analyses 
which  showed  the  most  marked  pollution.  Pradden  in 
1887  found  in  the  natural  ice  supplied  to  New  York  City 
a  wide  variation  in  numbers.  Many  other  observers  have 
come  to  similar  conclusions. 

The  author  and  his  assistants  in  an  extended  investiga- 
tion of  the  ice  supplies  of  Massachusetts  (see  Report  of  the 
Massachusetts  State  Board  of  Health  for  1889)  found  in 
the  natural  ice  of  that  state  (which  is  mostly  obtained  from 
ponds,  lakes  and  rivers)  very  few  living  bacteria  in  the 


258      ICE   AS   A  VEHICLE   OF   INFECTIOUS   DISEASE 

clear  ice  of  the  upper  layers,  but  considerable  numbers  in 
some  cases  in  the  lower  layers  and  in  the  "bubbly"  or 
"  snow  "  ice.  An  examination  of  the  artificial  ice  made 
in  Massachusetts  in  1892  proved  the  number  of  bacteria 
to  be  "  insignificant  under  the  prevailing  methods  of  manu- 
facture." (T.  M.  Drown,  Twenty-fourth  Annual  Report 
State  Board  of  Health  of  Massachusetts  (for  1892),  p.  598.) 
It  appears  to  be  certain,  therefore,  that  cold,  even  when 
extreme,  cannot  be  depended  on  to  kill  all  bacteria  whether 
pathogenic  or  saprophytic ;  and  both  natural  and  artificial 
ice  may,  and  generally  do,  contain  more  or  less  living 
micro-organisms. 

§  5. — Ice  as  a  Vehicle  of  Disease 

It  is  plain  from  what  has  been  said  in  the  last  paragraph 
that  ice  may  contain  living  pathogenic  germs.  It  may 
therefore  unquestionably  be  an  important  vehicle  of  disease. 
On  the  other  hand,  the  literature  of  the  subject  fails  to 
reveal  any  very  clear  evidence  that  it  has  been  hitherto  a 
vehicle  of  any  great  importance,  while  it  is  an  indubitable 
fact  that  certain  cities  which  have  used  ice  cut  from  sources 
known  to  be  infected  with  the  germs  of  typhoid  fever  have 
not  suffered  perceptibly  from  that  cause.  According  to 
Prudden,  the  ice  supply  of  New  York  City  was,  in  1888, 
largely  derived  from  the  Hudson  River  —  a  stream  highly 
polluted  by  the  sewage  of  Albany,  Troy  and  other  places 
in  which  much  typhoid  fever  existed.  Yet  a  study  of  the 
vital  statistics  of  New  York  City  does  not  support  the  idea 
that  much  typhoid  fever  is  conveyed  by  ice,  because  while 
ice  is  almost  universally  used  in  that  city  its  death-rate  from 
typhoid  fever  has  always  been  and  now  is  exceptionally 
low  for  an  American  city.  Boston,  on  the  other  hand, 
while  having  (as  New  York  also  has)  an  excellent  water 
supply,  is  supplied  with  ice  of  great  purity ;  and  yet  the 
death-rate  from  typhoid  fever  in  Boston  is  considerably 
higher  than  in  New  York.  Again,  the  cities  of  Lowell  and 


ICE   SUPPLY  AND   THE   PUBLIC   HEALTH          259 

Lawrence  have  long  been  supplied  chiefly  with  ice  cut  from 
the  polluted  and  infected  Merrimac  (cf.  pp.  207-212). 
Formerly,  owing  to  polluted  water  supplies,  both  suffered 
severely  from  typhoid  fever,  though  not,  as  might  have 
been  expected  if  ice  were  the  cause,  in  July  and  August 
when  ice  is  most  used,  but  generally  much  later.  With 
the  introduction  of  purer  water,  the  ice  supply  remaining 
the  same,  typhoid  fever  in  both  cities  has  fallen  to  the  level 
of  typhoid  fever  in  other  cities  in  Massachusetts  having  ice 
supplies  of  unquestioned  purity. 

It  was  from  the  consideration  of  facts  like  these  that  the 
author  was  led  to  undertake  the  investigation  which  is  de- 
tailed in  the  paper  by  himself  and  Mr.  Winslow,  and  to 
conclude  that  in  actual  everyday  life  ice  as  a  vehicle  of 
disease  is  probably  less  important  than  might  be  supposed 
if  one  had  in  view  only  the  fact  that  pathogenic  germs  may 
live  for  a  long  time  in  ice.  There  appear  to  be  fortunately, 
numerous  "mitigating  circumstances,"  numerous  conditions, 
which  serve  to  decrease  the  dangers  of  ice  as  a  vehicle  of 
disease.  And  if  all  the  facts  are  known  and  kept  in  mind, 
the  various  contradictory  phenomena,  which  at  first  seem 
hard  to  harmonize,  may  be  satisfactorily  explained. 

Briefly  stated,  the  more  important  facts  appear  to  be 
the  following :  ( I )  While  it  is  true  that  some  individual 
bacteria  survive  exposure  to  freezing  and  even  very  low 
temperatures,  such  conditions  are  highly  unfavorable  to 
bacteria  in  general,  even  of  the  same  kind,  especially  if  the 
exposure  be  prolonged.  Water  does  certainly  tend  to  purify 
itself,  and  under  ordinary  and  favorable  circumstances  does 
actually  and  extensively  purify  itself,  during  freezing.  On 
the  other  hand,  such  purification,  while  great,  is  usually 
incomplete.  (2)  Out  of  a  number  of  individual  bacteria  of 
any  kind  subjected  to  freezing  a  large  proportion  usually 
perish,  especially  if  they  continue  to  be  exposed  to  the  low 
temperature  for  two  or  three  weeks,  but  a  small  propor- 
tion survive.  (3)  There  is  good  reason  to  believe  that  the 


260     ICE   AS  A   VEHICLE   OF   INFECTIOUS   DISEASE 

efficiency  of  the  survivors  and  their  virulence  is  weakened 
both  by  their  loss  of  numbers,  and  by  freezing  or  by  long 
exposure  to  low  temperatures. 

These  facts  taken  together  with  those  already  mentioned 
above  enable  us  to  explain  all,  or  nearly  all,  the  phenomena 
in  question.  They  also  enable  us  to  draw  important  con- 
clusions concerning  the  dangers  of  the  pollution  of  ice,  and 
concerning  ice  supply  and  the  public  health. 

§  6.  —  The  Pollution  of  Ice 

Although  from  what  has  now  been  said  it  is  clear  that 
there  is  much  truth  in  the  popular  opinion  that  water  puri- 
fies itself  in  freezing,  it  is  equally  plain  that  too  much  reli- 
ance must  not  be  placed  upon  this  process.  Ice  should 
be  made  only  from  good  raw  materials,  i.e.  from  waters 
which  are  pure  and  potable ;  and  this  is  doubly  true  if 
"  artificial "  rather  than  "  natural "  ice  is  to  be  used  for 
public  or  private  supplies.  The  processes  of  harvesting 
natural  ice,  and  of  delivering  it  to  the  consumer,  still  leave 
much  to  be  desired.  The  use  of  horses  whose  droppings 
fall  on  the  ice  during  the  "ploughing"  or  cutting  of  the  ice 
fields ;  the  uncleanly  habits  of  the  workmen  employed ; 
the  floating  of  the  blocks  through  less  pure,  or  actually  pol- 
luted water,  on  their  way  to  the  ice-house ;  their  storage, 
often  in  a  packing  of  old  and  dirty  hay  or  sawdust ;  and 
their  final  delivery  into  family,  club  or  hotel  refrigerators 
by  common  workmen  after  only  hasty  brushing  with  some 
ancient  cloth  or  broom,  —  these  conditions  illustrate  the 
need  of  improvement.  Fortunately,  however,  ice  in  sum- 
mer is  usually  bathed  superficially  in  water  from  its  own 
melting  and  thus  roughly  cleansed,  so  that  grave  danger 
from  the  sources  mentioned  is  probably  relatively  rare. 

In  warm  countries  artificial  ice  is  much  used,  and  as  pro- 
cesses of  manufacture  improve,  it  is  likely  to  be  more  and 
more  used  everywhere.  The  author  is  strongly  of  the  opin- 


NATURAL  VS.  ARTIFICIAL  ICE  261 

ion  that,  generally  speaking,  such  ice  is  likely  to  be  inferior  to 
the  best  natural  ice.  It  is  liable  to  be  made  from  impure 
water ;  when  so  made  it  has  far  less  chance  to  purify  itself 
by  freezing;  and,  worst  of  all,  it  is  promptly  consumed;  so 
that  storage  and  the  destruction  of  any  microbes,  which  it 
may  contain,  by  exposure  for  a  long  time  to  unfavorable 
conditions  are  not  likely  to  occur.  It  is  worthy  of  note 
that  precisely  as  old  (or  stored)  water  is  preferable  to  new, 
so  also  is  old  (or  stored)  ice.  (Cf.  pp.  237,  249.) 

§  7. — Recapitulation 

From  what  has  now  been  said  we  may  derive  the  fol- 
lowing inferences  and  conclusions :  there  appears  to  be 
good  ground  for  the  popular  belief  that  natural  ice  con- 
siderably purifies  itself  in  freezing.  The  ideal  and  most 
favorable  condition  is  that  offered  by  a  lake  of  pure,  quiet 
and  deep  water  in  a  region  remote  from  human  habitation. 
In  such  a  case,  on  a  still,  cold  night,  the  surface  of  the  lake 
chilled  by  the  freezing  air  hardens  into  a  thin  and  delicate 
mirror  composed  at  first  of  shooting,  interlacing  crystals. 
Each  of  these,  as  it  forms  on  the  very  surface  of  a  mother- 
liquor  which  is  itself  almost  wholly  pure,  readily  pushes 
aside  most  foreign  substances  such  as  bacteria,  though  be- 
tween the  shafts  of  neighboring  crystals  or  on  their  surfaces 
a  few  may  be  caught  and  confined.  A  little  later,  the  first 
horizontal  skimming  of  ice  having  been  formed  by  the  inter- 
locking or  other  union  of  crystals,  fresh  crystals  send  shafts 
downward  into  the  now  more  quiet  water  just  beneath  them, 
and,  the  cold  continuing,  join  themselves  firmly  to  the  layer 
already  formed.  But  now  quiet  reigns  below  the  ice, 
and  gravity  incessantly  drags  downward  through  the  water 
everything  within  its  reach.  The  purest  layer  of  water, 
therefore,  is  now  the  highest,  and  into  this  fresh  crops  of 
crystals  are  steadily  growing  from  above.  Thus  it  happens 
that  the  uppermost  layer  of  the  ice  is  least  pure,  for  this 


262     ICE  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE 

includes  more  of  the  dust  of  the  air,  more  floating  matters, 
and  is  formed  without  any  overlying  sheltering  solid  layer 
such  as,  after  its  formation,  stills  the  water  and  shields 
the  under  layers.  This  ideal  condition,  however,  is  rarely 
found.  An  impure  pond  or  river  is  too  often  the  source 
of  supply.  A  sudden  freeze  often  follows  a  thaw  which 
has  made  turbid  and  dirty  the  waters  from  which  the  ice 
is  then  derived ;  or  a  snow  falling  during  a  dry  and  windy 
period  collects  from  the  air  a  vast  amount  of  dirt  and  falls 
upon  pure  ice,  finally  thawing  and  then  freezing,  only  to 
weld  itself  as  poor  and  porous  "  snow  ice  "  to  the  better, 
purer  ice  beneath  it. 

Still,  when  all  has  been  said  that  can  be  said  against  ice 
as  a  vehicle  of  disease,  and  while  it  cannot  be  denied  that 
ice  may  at  any  time  under  suitable  conditions  readily  serve 
as  such  a  vehicle,  it  nevertheless  remains  true  that  water 
certainly  strongly  tends  to  purify  itself  in  freezing,  and 
that  no  considerable  amount  of  disease  has  ever  been  satis- 
factorily traced  to  ice  either  as  source  or  vehicle.  As  a 
vehicle  of  disease,  ice  is  plainly  far  less  dangerous  to  the 
public  health  than  is  either  water  or  milk.1 

1  For  an  interesting  discussion  of  the  subject  of  "  Ice  Supply  and  the  Public 
Health,"  see  Journal  of  the  Massachusetts  Association  of  Boards  of  Health,  XI. 
4  (December,  1901),  pp.  123-143.  Also,  H.  W.  Hill,  M.D., "  An  Investigation 
of  the  Boston  Ice  Supply,"  Boston  Medical  and  Surgical  Journal,  November, 
21,  1901. 


CHAPTER  XI 

ON  MILK  AS  A  VEHICLE  OF  INFECTIOUS  DISEASE.  THE  POL- 
LUTION AND  INFECTION  OF  MILK.  MILK  SUPPLY  AND  THE 
PUBLIC  HEALTH 

§  i. — Milk  as  Food  for  Microbes  and  Mankind 

AMONG  all  the  vehicles  of  infectious  disease  there  is 
perhaps  none  more  dangerous  than  milk.  This  fact  is 
the  more  remarkable  because  milk  has  always  been  one 
of  the  most  trusted  of  human  foods.  Clothed  in  a  veil  of 
white ;  associated  with  the  innocence  of  infancy ;  of  high 
repute  for  easy  digestibility ;  believed  to  represent  in  per- 
fection a  natural  dietary,  popular  and  cheap,  —  milk  has 
always  deservedly  held  a  high  place  in  public  esteem.  Of 
late  years,  however,  while  maintaining  its  reputation  in 
respect  to  cheapness,  food  value,  blandness  and  digesti- 
bility, it  has,  in  the  eyes  of  physicians  and  sanitarians  at 
least,  come  to  be  regarded,  while  in  the  uncooked  condi- 
tion, with  general  suspicion.  The  principal  reason  for  this 
change  of  opinion  is  to  be  found  in  the  fact  that  numerous 
epidemics  of  infectious  disease  have  been  traced  with  more 
or  less  of  certainty  to  milk  supplies ;  while  the  development 
of  the  modern  science  of  bacteriology  has  tended  to  show 
that  milk  is  a  peculiarly  favorable  culture-medium  for  many 
species  of  bacteria,  and  may  be  therefore  justly  suspected 
of  serving  as  a  dangerous  vehicle  for  the  germs  of  infec- 
tious disease.  It  is  doubtful,  to  say  the  least,  whether  any 
disease  germs,  under  ordinary  circumstances,  ever  really 
multiply  in  a  fairly  good  drinking  water,  even  when  sew- 
age-polluted, owing  to  the  lack  of  a  favorable  environment; 

263 


264        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

but  the  very  qualities  which  make  milk  a  good  food  for  man- 
kind tend  to  make  it  likewise  a  good  food  for  microbes,  and 
there  is  only  too  much  reason  to  believe  that  under  certain 
circumstances  some  disease  germs  may  not  only  survive,  but 
even  multiply,  in  fresh,  pure  milk,  especially  if  it  be  kept 
warm. 

§  2.  —  Origin  of  the  Modern  Distrust  of  Uncooked  Milk 

For  the  reasons  given  in  the  preceding  paragraph,  there 
is  to-day  among  physicians  and  sanitarians  a  widespread 
distrust  of  uncooked  milk,  and  it  must  be  admitted  that  the 
more  the  subject  of  milk  supply  in  relation  to  the  public 
health  is  investigated,  the  more  cause  there  appears  to  be 
for  uneasiness.  Moreover,  the  conditions  under  which  cows 
are  kept,  and  the  opportunities  which  exist  for  the  pollution 
of  milk,  tend  to  confirm  rather  than  remove  this  distrust. 
Aside  from  the  fact,  which  would  be  regarded  as  highly 
peculiar  if  it  were  not  so  familiar,  that  milk  is  drawn 
directly  from  the  body  of  an  animal  and  therefore  occu- 
pies an  unique  position  among  all  human  foods  except 
that  of  infants,  there  remains  the  obvious  circumstance 
that  the  milk  supply  constitutes  one  of  the  oldest  indus- 
tries known  to  man.  There  is  every  reason  also  to  believe 
that  it  is  not  only  old,  but  old-fashioned. 

It  is  of  recent  years  only  that  milk  supply  has  come  to 
be  regarded  as  of  importance  to  the  public  health.  Pre- 
vious to  1 88 1  it  was  not  generally  known  that  milk  is  one 
of  the  readiest  vehicles  of  infectious  disease.  It  is  said 
that  the  first  epidemic  of  typhoid  fever  traced  to  milk  was 
one  in  1857,  studied  by  Dr.  Michael  Taylor.  In  1867  the 
same  epidemiologist  showed  that  scarlet  fever  might  be 
distributed  in  a  similar  way,  and  simultaneously  Professor 
Oswald  Bell  arrived  at  the  same  conclusion  through  his 
investigation  of  an  outbreak  of  that  disease.  In  1877  an 
epidemic  of  diphtheria  was  traced  to  a  milk  supply.  These 
and  other  cases  which  had  been  reported  were  brought 


MILK   AS   A  VEHICLE   OF   INFECTIOUS   DISEASE      265 

together  in  1881  by  Mr.  Ernest  Hart,  and  laid  before  the 
International  Medical  Congress  of  that  year  in  a  striking 
paper,  which  at  once  drew  universal  attention  to  milk 
supply  as  a  vehicle  of  infectious  disease.  Mr.  Hart  in  his 
paper  gave  the  history  of  fifty  epidemics  of  typhoid  fever, 
which  up  to  that  time  had  been  charged  to  infected  milk, 
besides  fifteen  epidemics  of  scarlet  fever,  and  four  of  diph- 
theria. "The  record,"  says  the  eminent  medical  writer 
from  whom  these  statements  are  taken,  "since  1881  has 
not  been  less  striking ;  indeed,  since  the  method  of  inves- 
tigating these  occurrences  has  been  more  generally  under- 
stood, milk  has  been  constantly  and  justly  incriminated  as 
a  cause  of  zymotic  disease  in  man." 

§  3.  —  The  Fermentations  of  Milk 

If  the  year  1881  was  important  to  the  milk-supply  indus- 
try and  the  public  health  for  the  reasons  just  mentioned, 
it  was  no  less  so  for  another  and  very  different  reason.  It 
will  be  remembered  that  it  was  in  this  year  that  Koch's 
method  of  solid  cultures  for  bacteria  was  introduced 
(see  p.  53),  and  this  method  soon  made  it  easy  to  investi- 
gate with  some  accuracy  the  ordinary  fermentations  of  milk 
by  observing  the  numerical  increase  of  its  bacterial  fer- 
ments and  their  variety,  while  also  studying  their  progres- 
sive effects  upon  the  milk  itself.  The  same  method,  which 
in  other  fields  led  to  the  discovery  and  elaborate  study  of 
the  special  ferments  or  germs  of  certain  infectious  diseases, 
such  as  typhoid  fever,  Asiatic  cholera  and  diphtheria,  made 
possible  also  the  study  of  the  behavior  of  these  germs  in 
milk,  with  the  result  that  evidence  was  quickly  obtained 
proving  that  under  certain  circumstances,  milk  offered  to 
them  an  admirable  culture-medium. 

Further  investigations  along  these  lines  have  shown  that 
city  milk  is  often  in  an  advanced  stage  of  decomposition, 
and  therefore  far  removed  from  the  normal  milk  which  is 


266        MILK   SUPPLY   AND  THE  PUBLIC   HEALTH 

drawn  by  the  infant  from  the  mammary  gland  of  the 
mother.  It  has  long  been  known  that  bottle-fed  babies  in 
cities  show  a  much  heavier  mortality  than  those  fed  nor- 
mally ;  and  investigations  appear  to  have  proved  that  this 
is  due,  in  part  at  least,  to  the  unsatisfactory  condition  of 
city  milk  supplies.  It  is  now  well  known  that  city  milk  is 
not  only  often  falsified,  but  also  frequently  filthy,  stale  and 
half  fermented.  Moreover,  the  facts  that  tuberculosis  is 
the  cause  of  death  of  a  larger  number  of  persons  than  die 
of  any  other  disease,  and  that  tuberculosis  is  known  to  be 
common  hi  cows,  have  naturally  led  many  to  suppose  that 
numerous  cases  of  this  disease  are  due  to  the  consumption 
of  milk.  More  recently,  also,  it  has  been  alleged  on  good 
authority  that  the  mixed  milk  of  a  number  of  cows  is 
seldom  free  from  pus. 

§  4.  —  Normal  versus  Fermented  Milk 

By  "normal"  milk  is  meant  milk  as  it  flows  from  the 
teat  of  a  healthy  and  well-fed  mammal.  Such  milk  is,  as 
a  rule,  free  from  putrefactive  bacteria.  (Cf.  §  7.) 

Almost  immediately,  however,  normal  milk  is  invaded  by 
a  host  of  such  bacteria,  which  find  their  way  into  it  from  the 
air,  the  dust  of  the  stable,  the  cheesy  remains  of  previous 
milkings  in  the  angles  of  the  pails  and  other  appliances, 
the  hide  of  the  cow,  or  the  hat  or  hands  of  the  milker. 
It  is  held,  also,  that  normal  milk  may  be  seeded  with  bac- 
teria even  before  leaving  the  teat,  the  so-called  "foremilk  " 
having  been  found  by  numerous  observers  to  contain  a  con- 
siderable number  of  bacteria,  which  are  supposed  to  have 
come  from  infection,  from  without,  of  the  milk  in  the  main 
duct  of  the  teat.  However  this  may  be,  there  is  no  ques- 
tion that  normal  milk  is  relatively  free  from  bacteria,  and 
fresh  or  unfermented. 

It  is  worth  while  to  observe,  in  passing,  that  normal  milk, 
under  natural  conditions,  arrives  in  the  stomach  of  the 


IMPORTANCE   OF   SANITARY  MILK   SUPPLIES     267 

suckling  almost  instantly  after  leaving  the  teat ;  for,  as  we 
shall  show,  milk  as  obtained  in  cities  and  from  public  sup- 
plies in  general  is  very  different  in  this  respect.  City  milk 
is  always  more  or  less  old  and  fermented,  more  or  less  stale 
and  more  or  less  dirty.  Between  the  time  of  its  leaving  the 
teat  and  its  arrival  in  the  stomach  of  the  bottle-fed  city 
infant,  cow's  milk  has  too  often  travelled  over  a  long  dis- 
tance ;  too  often  undergone  damaging  exposure  to  dirt  and 
air;  and  too  often  suffered  extensive  fermentation  or  decom- 
position. It  is  impossible  to  avoid  the  conclusion  that  it  is, 
for  these  reasons,  comparatively  abnormal. 

§  5. — Infantile  Diarrhoea  and  Cholera  Infantum 

Various  observers  have  attributed  to  unsound  milk,  not 
only  the  high  death-rate  of  bottle-fed  infants  in  cities, 
but  also  certain  special  diseases,  such  as  the  infantile 
diarrhoea  of  summer  and  cholera  infantum.  There  is  rea- 
son to  believe  that  in  many  instances,  at  least,  unsound 
milk  has  much  to  do  with  these  disorders,  and  in  support 
of  this  view  it  is  urged  that  the  substitution  of  cooked 
(Pasteurized  or  sterilized)  milk,  for  uncooked  or  raw  milk 
swarming  with  bacteria,  does  away  in  a  large  measure  with 
the  troubles  referred  to.  It  is  perhaps  still  too  early  to 
speak  with  accuracy  on  this  subject,  but  the  tendency  cer- 
tainly is,  among  those  who  have  looked  into  the  matter,  to 
consider  unsound  milk  as  the  source  of  many  of  the  most 
serious  troubles  of  infancy.  Experiments  conducted  in 
hospitals  and  nurseries  seem  amply  to  justify  this  conclu- 
sion, and  the  supreme  importance  of  a  sanitary  milk  supply 
for  such  establishments  is  now  generally  conceded. 

§  6.  —  The  Pollution  of  Ordinary  Milk 

Bacteriologic  and  microscopic  examinations  reveal  the 
fact  that  ordinary  city  milk  is  highly  polluted.  Numerous 
observers  all  over  the  world  have  reported  the  presence  in 


268        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

ordinary  city  milk  of  vast  numbers  of  bacteria ;  and  inquiry 
as  to  the  source  of  these  micro-organisms  has  led  to  the  dis- 
covery that  milk  is  too  often  polluted,  to  a  serious  degree, 
by  the  dust  of  the  air,  the  dung  of  the  stable,  and  the  un- 
cleanness  of  pails,  cans  and  other  milking  utensils,  such 
pollution  being  unfortunately  hidden  by  the  opacity  of 
milk,  and  unsuspected  because  of  the  idea  of  purity  usually 
associated  with  its  color.  The  fact  appears  to  be  that  the 
dairy  industry  is,  as  a  rule,  still  in  a  very  primitive  condition. 
The  following  realistic  statement,  made  in  the  author's 
hearing  by  a  member  of  a  suburban  Board  of  Health, 
describes  a  condition  which  was  only  too  common  in  rural 
New  England  in  the  last  quarter  of  the  nineteenth  century, 
and  has  not  yet  wholly  disappeared. 

"  If  we  consider  merely  the  matter  of  cleanliness  and  the  prevention 
of  filth  in  milking  the  cows  and  taking  the  product  to  market,  we  still 
have  a  very  large  and  difficult  question  to  deal  with.  No  doubt  Boards 
of  Health  can  do  something  to  improve  cow  stables,  to  secure  better 
ventilation,  and  more  cleanliness  —  they  can  do  something;  but  from 
what  I  have  seen  myself  (and  I  was  brought  up  on  a  farm),  I  know 
that  a  large  part  of  the  filth  which  gets  into  the  milk  gets  there  in  ways 
beyond  the  direct  control  of  Boards  of  Health,  for  it  gets  there  by  the 
careless  behavior  of  the  milker. 

"The  day  has  gone  by  when  a  pretty  milkmaid  went,  in  clean,  white 
apron  and  with  shining  milk  pail,  to  milk  the  cow  with  the  crumpled 
horn  out  among  the  buttercups  of  a  dewy  morning.  Instead,  some  old 
fellow  stumbles  out  of  the  house  and  to  the  barn,  with  the  stump  of  a 
clay  pipe  in  his  mouth,  and  wearing  overalls  and  boots  saturated  and 
covered  with  the  filth  acquired  by  a  winter's  use.  When  he  reaches 
the  barn  he  selects  some  recumbent  cow,  kicks  her  until  she  stands  up, 
dripping  and  slimy,  and  as  he  is  a  little  late  and  the  milk  will  have 
hardly  time  to  cool  before  the  man  who  carries  it  to  the  city  will  come 
along,  he  does  not  stop  to  clean  up  behind  the  cow,  but  sitting  down 
on  a  stool,  proceeds  to  gather  the  milk  and  whatever  else  may  fall  into 
a  pail  which  perhaps  is  clean  and  perhaps  is  not.  Of  such  refinements 
as  washing  the  udder  of  the  cow  or  wiping  her  flanks,  he  has  never 
heard.  If  he  has,  it  is  only  to  scoff.  Then  he  strains  the  milk  behind 
the  cows.  That  is  bad  enough,  but  it  is  not  all  the  story.  Every  one 
knows  that  in  straining  the  milk  the  strainer  becomes  obstructed  more 


THE   POLLUTION   OF  MILK  269 

or  less  with  dirt  and  filth,  and  when  the  milk  does  not  run  fast  enough, 
he  would  be  a  rare  milker  who  hesitated  to  scrape  away  a  place  with  his 
fingers  so  that  the  milk  might  run  more  freely.  Those  who  have  seen 
certain  fingers,  as  I  have,  know  what  that  means."  —  E.  IRVING  SMITH. 
Journal  Massachusetts  Association  of  Boards  of  Health,  II,  2,  p.  33 
(1892). 

§  7.  —  Systems  of  Public  Milk  Supply.     (A)  Normal  Milk 

Supplies 

The  primitive,  original  and  fundamental  form  of  milk 
supply  is  that  in  which  the  mammal  —  cow,  camel,  elephant, 
goat,  sheep,  mare  or  man  —  suckles  its  young.  In  this  case, 
the  milk  supplied  by  the  parent  passes  almost  instantane- 
ously from  the  milk  gland  into  the  stomach  of  the  young 

—  without  lapse  of  time,  without  exposure  to  air  or  vessels, 
without  human  handling,  manipulation  or  falsification  — 
precisely  as  nature  has  prepared  it.     The  only  possibility 
of  fault  to  be  found  with  it,  from  the  sanitary  standpoint, 
is  the  opportunity  of  damage  from  the  parent,  in  case  that 
parent  is  unhealthy  or  ill  fed.     If  the  parent  is  healthy 
and  well  fed,  such  milk  deserves  the  name  of  normal  milk. 
Normal  cow's  milk,  then,  may  be  defined  as  milk  as  it 
flows  from  the  udder  of  a  healthy  and  well-cared-for  cow. 

§  8. — (B)  Country,  or  Domestic,  Milk  Supplies 

Next  in  complexity  comes  the  private,  or  domestic, 
supply,  in  which  a  family  obtains  its  milk  from  its  own 
cow  or  cows.  This  is  the  system  which  prevails  on  ordi- 
nary farms  and  in  small  villages,  and  survives  sometimes 
as  a  luxury  of  the  wealthy,  even  in  large  cities.  In  this 
case  the  milk  is  no  longer  strictly  normal.  Between  the 
producer  (the  cow)  and  the  consumer  (the  individual  who 
swallows  the  milk)  have  come  in  one  or  more  middlemen, 

—  the  milker,  the  housewife,  the  housemaid,  as  may  be. 
Moreover,  the  milk  has  been  more  or  less  exposed  to  air, 
—  possibly  dust-laden,  and   always   carrying   microscopic 


2/0        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

germs  of  fermentation;  to  vessels,  —  pails,  pans,  strainers, 
—  often  richly  seeded  with  similar  microscopic  organisms ; 
and  time  has  elapsed,  longer  or  shorter,  so  that  these 
organisms  have  caused  the  milk  to  "work"  or  ferment, 
slightly  or  extensively  as  the  case  may  be.  This  in  itself 
marks  a  departure,  often  trifling  but  always  real,  from  the 
absolutely  normal  milk  supply,  such  as  calves  and  infants 
naturally  enjoy.  The  sources  of  danger  are  here  much 
increased,  for  it  is  no  longer  merely  the  question  of 
having  a  healthy,  well-fed  parent;  we  have  now  also 
to  consider  a  possible  contamination  by  the  milker,  the 
housewife,  or  other  "  middleman,"  before  the  milk  enters 
the  stomach  of  the  consumer,  and  also  those  natural  altera- 
tions which  milk  undergoes  after  being  seeded  with  the 
germs  of  fermentation,  during  the  time  which  elapses 
between  its  exit  from  the  teat  of  the  cow  and  its  entrance 
into  the  stomach.  In  well-regulated  families,  however, 
the  risk  of  damage  so  resulting  is,  from  a  sanitary  point 
of  view,  comparatively  slight ;  and  those  are  fortunate  who 
may  enjoy  the  privilege  of  possessing  a  milk  supply  of  this 
simple,  primitive  kind. 

Not  by  any  means  the  least  important  fact  in  this 
domestic  system  of  supply  is  the  possibility  of  complete, 
personal  acquaintance  on  the  part  of  the  consumer  with 
the  sources  of  his  supply,  and  a  consequent  more  or  less 
extensive  control  over  them.  This,  as  we  shall  see,  he 
almost  unconditionally  surrenders  when  he  becomes  an 
ordinary  dweller  in  a  great  city. 

§  9. — (C)   Village  or  Suburban  Milk  Supplies 

As  man  comes  to  live  in  larger  villages  and  towns,  some 
families  give  up  the  keeping  of  cows  and  buy  milk  of  their 
neighbors,  who,  in  order  to  supply  them,  keep  more  cows. 
The  personal  acquaintance  of  the  consumer  with  the  exact 
sources  of  his  supply  diminishes,  and  his  personal  control 


VARIOUS   SYSTEMS   OF  MILK   SUPPLY  27 1 

is  somewhat  relaxed,  though  he  still  keeps  up  a  general 
knowledge  and  supervision,  and  may,  if  he  chooses,  know 
and  do  more  about  his  milk  supply  at  any  time.  But,  as 
the  neighbor  who  supplies  him  keeps  more  cows,  and  more 
men,  and  uses  more  cans,  and  needs  more  time  to  distribute 
his  milk,  each  possible  source  of  damage  to  the  milk  becomes 
more  important  and  the  departure  from  the  normal  is,  neces- 
sarily, gradually  and  constantly  greater. 

§  10. — (D)  City  (Railroad}  Milk  Supplies 

Finally,  as  the  city  continues  to  grow  larger,  the  milk 
farms  are  pushed  farther  and  farther  away,  until  a  state 
of  things  is  reached  in  which  the  farmer  can  no  longer 
himself  deliver  milk  to  the  consumer,  even  with  the  aid  of 
fleetest  horses.  The  railroad  is  called  in,  the  contractor, 
or  some  similar  middleman,  appears,  and  the  farmer  now 
becomes  merely  the  producer.  But  the  consumer  cannot 
send  to  the  railroad  for  his  milk,  and  so  another  carrier, 
with  special  wagons  adapted  to  the  purpose,  passes  to  and 
fro  between  the  railroad  and  the  consumer.  This  person 
is  known  to  the  consumer  as  "  his  milkman " ;  but,  as  a 
rule,  he  is  a  very  different  kind  of  person  from  the  farmer, 
the  original  type  of  "milkman."  In  this  final  form  of  milk 
supply  the  producer  may  have  no  idea  whatever  of  the 
final  destination  of  his  milk;  and  the  consumer,  as  a  rule, 
neither  knows  nor  cares  where  the  milk  which  he  buys 
comes  from.  The  personal  relation  between  consumer 
and  producer  is  totally  lost,  and  the  middleman  comes  to 
hold  the  position  of  principal  importance,  as  the  only  per- 
son in  touch  with  all.  These  circumstances,  and  the  very 
size  of  the  system,  tend  to  make  it  largely  mechanical,  and 
all  connected  with  it  merely  subordinate  parts  in  a  great 
machine  which,  for  good  or  ill,  must  work  on  incessantly. 

With  the  rapid  growth  of  cities  and  the  development  of 
railroad  facilities,  it  is  likely  that  something  like  the  sys- 


2/2         MILK   SUPPLY   AND   THE   PUBLIC  HEALTH 

tern  last  described,  and  which  now  holds  good  only  for  the 
largest  cities,  will  come  to  exist,  to  a  greater  or  less  extent, 
even  in  smaller  communities,  and  it  is  well  that  these  ten- 
dencies, which  concern  farmers,  middlemen  and  consumers 
alike,  should  be  carefully  noted  by  the  sanitarian. 

Under  this  system  the  milk  is  often  two  days  old,  and 
therefore  relatively  stale  and  half  fermented,  before  it  is 
actually  consumed.  It  also  necessarily  passes  through 
many  hands  en  route,  and  is  therefore  accessible  to  manipu- 
lation, adulteration  and  contamination. 

§  II. — Milk  Supply  in  Hot  Countries 

In  tropical  countries  the  systems  of  public  supply  just 
described  do  not  usually  prevail,  doubtless  owing  to  the 
fact  that  ice  is  not  ordinarily  available,  and  even  if  it  were, 
might  be  inadequate  for  the  satisfactory  preservation  of 
the  milk. 

It  is  said  that  among  the  Arabs  milk  is  either  consumed 
absolutely  fresh  when  drawn  from  the  cow,  or  else  is 
allowed  to  sour  before  it  is  used.  In  Naples,  and  many 
other  cities  in  warm  climates,  cows  or  goats  are  driven 
through  the  streets,  and  milked  by  their  owners  before  the 
doors,  and  in  the  presence  of,  the  consumers.  The  herds 
of  goats  thus  driven  slowly  through  the  streets  of  conti- 
nental cities,  led  by  a  goat-herd  playing  on  some  simple 
musical  instrument,  are  familiar  sights  to  travellers.  It  is 
stated  that  the  Chinese  never  drink  either  water  or  milk 
without  first  having  boiled  it. 

In  all  these  and  other  customs  of  mankind  regarding 
milk  supplies,  the  sanitarian  can  readily  trace  the  results 
of  human  experience.  Absolutely  fresh  milk,  approaching 
as  it  does  the  normal  condition,  is  almost  everywhere  a 
favorite  food.  If,  however,  owing  to  local  conditions,  such 
as  density  of  population,  climate  or  the  nomadic  habit, 
milk  cannot  be  obtained  absolutely  fresh,  it  is,  and  should 


MILK   AS  A  VEHICLE   OF  TYPHOID   FEVER        273 

be,  either  cooked  or  soured  before  it  is  used.  By  cookery, 
the  germs  of  decomposition  and  infection  are  destroyed; 
by  souring,  acid  is  produced,  which  is  similarly  unfavorable 
to  many  germs  of  decomposition  and  infectious  disease. 


§  12. — Epidemics  of  Typhoid  Fever  in  Massachusetts 
traced  to  Infected  Milk  Supplies 

Several  extensive  epidemics  of  typhoid  fever  in  Mas- 
sachusetts have  been  traced  to  infected  milk  supplies, 
and  the  same  thing  is  true,  generally  speaking,  all  over 
the  world.  As  the  author  is  naturally  most  familiar  with 
those  epidemics  which  he  has  himself  investigated,  he 
has  chosen  for  illustration  examples  drawn  from  his  own 
experience. 

§  13. —  The  Springfield  Epidemic^ 

In  August,  1892,  the  State  Board  of  Health  of  Massa- 
chusetts was  informed  by  the  local  Board  of  Health  of 
Springfield  that  an  epidemic  of  typhoid  fever  had  appeared 
in  that  city.  Investigation  showed  that  the  cases  were  not, 
as  might  have  been  expected,  among  the  poorer  classes  of 
the  people,  nor  in  the  midst  of  unsanitary  surroundings,  but 
in  a  district  well  provided  with  sewers,  by  no  means  over- 
crowded, inhabited  by  a  superior  class  of  citizens  dwelling 
for  the  most  part  in  separate  and  detached  houses  of  high 
grade,  each  house  surrounded  by  a  lawn  or  grass  plot,  and 
standing  somewhat  back  from  the  street.  The  plumbing 
arrangements  were  unusually  satisfactory,  because  the 
houses  were  new  and  their  owners  well-to-do. 

Various  theories  prevailed  among  the  people  to  account 
for  the  epidemic,  but  all  of  these  were  easily  disproved 
except  that  which  attributed  the  cause  to  an  infected  milk 

1  For  the  full  report,  illustrated  by  diagrams,  see  Twenty-fourth  Annual 
Report  State  Board  of  Health  of  Massachusetts  (for  1892),  p.  715.  Boston, 
1893- 

T 


2/4        MILK   SUPPLY  AND  THE  PUBLIC   HEALTH 

supply.  Almost  every  one  of  the  persons  affected  with 
the  disease  was  shown  to  have  swallowed  milk  supplied 
by  a  particular  milkman,  and  patient  inquiry  eventually 
revealed  the  fact  that  the  milk  distributed  by  the  milkman 
in  question  was  derived  from  a  farm,  several  miles  from 
the  city,  upon  which  there  had  lately  been  a  case  of 
typhoid  fever.  The  excreta  of  the  patient  had  not,  at  least 
for  a  time,  been  satisfactorily  disinfected,  and  in  one  or 
more  of  several  ways  had  probably  found  access  to  the 
milk  produced  on  the  farm  and  sent  to  Springfield. 

§  14. —  The  Somerville  Epidemic^ 

In  the  same  year  (1892)  a  small  epidemic  of  typhoid 
fever  appeared  in  a  particular  section  of  Somerville,  Mass. 
Inquiry  soon  showed  that  all  of  the  cases  were  supplied 
with  milk  by  one  milkman.  This  time  no  typhoid  fever 
was  discovered  on  the  farms  from  which  the  milk  was  de- 
rived, but  it  was  finally  disclosed  that  a  son  of  the  milk- 
man, whose  duty  it  was  to  transfer  the  milk  -from  the 
larger  cans,  in  which  it  came  from  the  farms  by  railroad 
to  the  city,  to  the  little  cans  in  which  it  was  furnished  to 
the  consumers,  and  who  in  various  ways  came  more  or  less 
in  contact  with  the  milk,  had  been  himself,  a  little  earlier, 
a  sufferer  from,  and  was  finally  a  victim  of,  typhoid  fever, 
and  the  probable  source  of  the  disease  among  his  customers. 

§  15. —  The  Cambridge  Epidemic 

In  August,  1896,  a  considerable  epidemic  of  typhoid 
fever  appeared  in  the  city  of  Cambridge,  Mass.,  and  it 
soon  became  evident  that  it  was  due  to  infected  milk. 
Subsequent  investigation  revealed  the  fact  that  here  also, 
as  in  the  Somerville  case,  no  typhoid  fever  existed  on  the 
farms  from  which  the  milk  was  derived ;  but  that  among 

i  Op.  cit.,  footnote,  p.  273. 


•      MILK  AS   A  VEHICLE   OF   TYPHOID   FEVER        2/5 

the  workmen  who  manipulated  the  milk  in  the  milk-house 
of  the  local  (Cambridge)  dealer  there  existed  two,  and 
possibly  three,  mild,  and  at  first  unrecognized,  cases  of 
typhoid  fever. 


§  1 6. — Epidemics  traced  to  Skimmed  (Separated)  Milk, 
and  Creameries 

In  August  and  September,  1894,  a  small  epidemic  of 
typhoid  fever  appeared  in  the  city  of  Marlborough,  Mass. 
Various  "theories"  of  the  cause  of  the  outbreak  were 
held  or  suggested,  and  the  local  newspapers  contained 
numerous  letters  on  the  subject,  some  alleging  that  the 
water  supply  was  infected,  some  that  the  sewers  were  to 
blame,  and  some  that  accumulations  of  filth,  especially 
dump-heaps,  were  responsible.  The  localization  of  the 
cases,  however,  not  only  disproved  these  "theories,"  but 
also  suggested  milk  as  the  probable  cause. 

It  soon  became  evident,  nevertheless,  that  none  of  the 
regular  milkmen  were  involved,  the  cases  apparently 
deriving  their  milk  supplies  from  a  variety  of  different 
sources.  Eventually,  however,  it  turned  out  that  there 
existed  within  the  city  itself  a  creamery  from  which  was 
despatched  daily  a  wagon  loaded  with  skimmed  milk  ("sepa- 
rator" milk),  and  that  nearly  all  the  cases  of  typhoid  fever 
had  been  supplied  with  such  skimmed  milk  either  from  this 
wagon  or  directly  from  the  creamery  itself.  Further  inves- 
tigation showed  that  the  driver  of  the  skimmed-milk  wagon 
was  at  the  time  of  the  inquiry  living  on  the  upper  floor  of 
the  creamery,  and  just  recovering  from  a  severe  attack 
of  typhoid  fever.  This  young  man  had  not  only  been 
the  driver  of  the  wagon,  but  had  also  worked  over  the 
milk,  transferring  it,  filling  the  cans,  and  otherwise  making 
himself  useful  about  the  creamery.  In  the  investigation 
of  this  case,  which  was  made  by  the  author  on  behalf  of 
the  State  Board  of  Health  of  Massachusetts,  aid  was  de- 


2/6        MILK   SUPPLY  AND   THE   PUBLIC   HEALTH 

rived  from  the  report  of  Dr.  Welply,  then  recently  pub- 
lished, on  an  epidemic  of  typhoid  fever  traced  by  him  to  a 
creamery  in  Ireland,  and  disseminated  by  separator  milk.1 
In  this  case  milk  from  a  farm  belonging  to  a  family  suf- 
fering from  typhoid  fever  was  taken  to  a  creamery,  and 
appears  there  to  have  infected  the  whole  mass  of  separated 
or  skimmed  milk,  through  which  it  was  distributed  to 
numerous  other  families.2  In  the  reprint  of  Dr.  Welply's 
papers  "  four  other  epidemics  due  to  separated  milk  "  are 
referred  to. 

§  17. —  The  Question  of  Tuberculosis  in  Milk 

Inasmuch  as  milk  is  one  of  the  most  universally  trusted 
and  widely  employed  of  foods,  while  cows  are  known  to 
suffer  seriously  from  tuberculosis  and  this  disease  sur- 
passes all  other  diseases  as  an  agent  of  death  in  the 
human  family,  milk  has  naturally  fallen  under  the  gravest 
suspicion  as  a  vehicle  of  tuberculosis.  Satisfactory  proof 
of  any  such  complicity  as  is  suspected  is,  however,  exceed- 
ingly difficult  to  obtain.  Owing  to  the  fact  that  tuber- 
culosis is  commonly  a  disease  of  slow  development,  it  is 
almost  impossible  to  trace  any  particular  case  in  the  human 
family  to  any  particular  infection,  and  the  very  abundance 
of  opportunities  for  infection  makes  it  hard  to  prove  that 
one,  and  only  one,  source  existed.  It  is  hard  to  resist  the 
belief  that  if  a  cow  is  suffering  from  tuberculosis  of  the 
udder,  her  milk  is  tolerably  certain  to  be  infected.  Nor  is 
it  necessary  even  to  assume  the  presence  of  udder  tuber- 
culosis in  order  to  admit  the  possible  infection  of  milk. 
Cows  affected  with  pulmonary  tuberculosis  may,  and  often 

1  Dr.  J.  J.  Welply,  "Creameries  and  Infectious  Disease,"  The  Lancet, 
April  21,  1894.  See  also,  by  the  same  author,  "  Creameries  and  Infectious 
Diseases,"  London,  Balliere,  Tindall  and  Cox,  1895. 

8  For  a  full  account  of  the  Marlborough  epidemic,  see  report  by  the  author 
in  Twenty-sixth  Annual  Report  State  Board  of  Health  of  Massachusetts  (for 
P-  765- 


MILK   AS  A  VEHICLE   OF   TUBERCULOSIS          2/7 

do,  lick  their  own  flanks  or  udders  and  those  of  other  cows, 
and  conceivably  may  readily  leave  there  fresh  germs  of 
tuberculosis  from  their  sputum,  which  germs,  barely  dried, 
may  soon  after  fall,  or  be  brushed  during  milking,  into  the 
milk  pail. 

As  a  matter  of  fact,  germs  apparently  identical  with  those 
of  tuberculosis  have  been  detected  by  microscopical  exami- 
nation in  the  milk  of.  cows  in  which  no  udder  disease  could 
be  discovered  by  physical  signs,  and  these  may  have  got 
in  in  the  way  suggested.  We  may  remark,  in  passing,  that 
such  examinations  are  not  competent  to  determine  whether 
the  germs  in  question  are  alive  or  not.  This  point  can 
only  be  determined  by  cultivations,  or,  better,  by  inocula- 
tion experiments. 

The  most  instructive  and  valuable  evidence  that  we 
have  comes  from  inoculation  experiments,  in  which  a  num- 
ber of  healthy  susceptible  animals  (guinea-pigs  are  gen- 
erally used)  are  selected,  and  divided  at  random  into  two 
groups.  One  group  is  kept,  as  a  control,  under  conditions 
precisely  similar  to  those  of  the  other,  except  that  its 
members  are  not  inoculated.  To  the  members  of  the 
other  group  are  given  subcutaneous  injections  of  milk 
suspected  to  contain  the  bacilli  of  tuberculosis.  In  cer- 
tain experiments  of  this  kind  the  inoculated  animals  have 
actually  perished  after  a  time  with  tuberculosis,  while  the 
corresponding  control  animals  have  kept  free  from  it. 
Such  experiments  certainly  seem  to  prove  beyond  all 
question  that  milk  may  be  a  vehicle  of  tuberculosis.  They 
do  not,  however,  prove  that  bovine  tuberculosis  is  as  readily, 
if  it  be  at  all,  communicable  to  human  beings  by  milk ;  and 
we  have  experimental  evidence  that  human  tuberculosis  is 
not  readily,  if  ever,  conveyed  to  cattle.  The  whole  sub- 
ject, in  brief,  requires  further  elucidation. 

Reports  of  cases  in  which  a  family  used  the  milk  of 
a  tuberculous  cow  and  afterward  suffered  severely  from 
tuberculosis,  should  be  received  with  caution.  They  are 


278        MILK   SUPPLY  AND   THE   PUBLIC   HEALTH 

almost  always  open  to  the  suspicion  and  the  possibility  of 
being  examples  of  coincidence,  rather  than  cause. 

§  1 8.  —  Scarlet  Fever  and  Diphtheria  in  Milk 

A  number  of  epidemics  of  scarlet  fever  and  diphtheria 
have  been  attributed  to  milk  as  a  vehicle,  but  the  number 
is  small  in  comparison  with  those  of  typhoid  fever  traced 
to  milk.  Moreover,  a  careful  review  of  the  evidence  in 
these  cases  is  calculated  to  leave  the  student  somewhat 
less  well  satisfied  that  milk  was  really  in  some  of  the  in- 
stances the  sole  vehicle  of  the  disease. 

§   19.  —  The  Protection  of  Milk  Supplies  from  Pollution 

The  milk-supply  industry,  as  has  been  said  above,  is  still 
to  a  great  extent  in  a  primitive  condition.  The  ordinary 
dairy  farmer,  no  matter  how  honest  or  well-meaning,  often 
has  not  the  smallest  conception  of  the  sanitary  aspects  of 
his  art.  It  is  exceedingly  unfortunate  that  dirt  in  milk 
cannot  readily  be  observed,  and  that  the  characteristic  odor 
of  milk  masks  to  a  great  extent  evidences  of  decomposition 
which  might  otherwise  be  plain.  What  is  needed  is  a  cam- 
paign of  education  among  the  farmers  who  produce  milk, 
concerning,  first,  the  simple  protection  of  a  readily  putres- 
cible  fluid  from  pollution  with  dirt  and  other  elements  of 
decay;  and,  second,  the  sanitary  protection  of  milk  from 
infection.  It  is  no  doubt  a  difficult  matter  to  make  sure  that 
the  hands  and  the  clothing  of  the  milkers  of  cows  shall  be 
thoroughly  clean ;  that  the  udder  and  teats  shall  be  washed, 
or  at  least  wiped  thoroughly  with  a  damp  cloth,  before  the 
milking  begins ;  that  the  tail  of  the  cow  shall  not  make  even 
occasional  excursions  through  the  pail  during  the  milking ; 
that  cows  shall  be,  like  horses,  groomed  and  kept  clean  so 
that  caked  dung  shall  not  cling  to  their  flanks,  to  drop,  with 
dandruff  from  their  hides,  into  the  pail ;  that  pails  and  cans 
and  strainers  shall  be  sterilized  with  steam  or  scalding 


THE   INFECTION   OF  MILK  279 

water  so  thoroughly  that  yellowish  cheesy  matter  alive 
with  myriads  of  bacteria  shall  not  fill  their  corners  or 
cracks ;  but  it  is  these  simple  items,  indispensable  to 
cleanness,  which,  carefully  attended  to,  will  not  only 
improve  the  milk,  from  a  sanitary  point  of  view,  but  also 
prolong  its  "life"  or  keeping  qualities,  and  thereby  in 
the  end  richly  reward  the  producer  who  is  willing  to 
"take  pains."  (Cf.  note  on  p.  392.) 

It  should  never  be  forgotten  that  if  drinking  water 
were  to  be  drawn,  as  milk  is,  from  the  body  of  a  cow 
standing  in  a  stable,  by  the  hands  of  workmen  of  ques- 
tionable cleanness,  and  then  stored  and  transported  over 
long  distances  in  imperfectly  cleaned,  closed  cans ;  being 
further  manipulated  more  or  less,  and  finally  left  at  the 
door  at  an  uncertain  hour  of  the  day,  few  would  care 
to  drink  it,  because  its  pollution  and  staleness  would 
be  obvious.  It  is  clear,  moreover,  that  milk  requires, 
and  deserves,  even  more  careful  treatment  than  water,  for  it 
is  more  valuable,  more  trusted  and  more  readily  falsified  or 
decomposed.  Nevertheless,  until  very  lately,  milk  while 
legally  protected  from  dilution  by  water  has  received  little 
or  no  attention  from  boards  of  health  on  the  simple  ques- 
tion of  pollution.  It  is  cheering  to  observe,  therefore,  that 
steps  are  at  last  being  taken  even  in  this  direction. 

• 

§  20.  —  The  Protection  of  Public  Milk  Supplies  from 
Infection 

It  will  be  convenient  and  natural  to  divide  this  subject 
into  two ;  namely,  (a)  protection  from  infection  by  man,  and 
(U]  protection  from  infection  by  the  cow. 

(a)  The  occurrence  of  numerous  epidemics,  in  which  it 
appeared  that  some  person  or  persons  working  over  the 
milk  had  infected  it,  has  led  to  rules  and  regulations  — 
often  having  the  force  of  laws  —  governing  the  conduct  of 
dairies  by  persons  known  to  be  diseased,  or  otherwise  aim- 


280        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

ing  to  protect  the  public  health.  To  a  brief  consideration 
of  these  we  shall  come  in  the  next  section.  Here  we  shall 
simply  seek  to  develop  the  principles  which  should  under- 
lie such  rules  and  regulations  by  considering  in  detail  how, 
precisely,  cows'  milk  may  become  infected  from  sources 
other  than  the  cow,  and  especially  through  human  beings. 

Milk  may  become  infected  almost  as  soon  as  it  is  drawn 
from  the  cow  by  germs  derived  from  the  hands  of  the 
milker  or  from  his  clothing.  If,  for  example,  a  milkman 
or  milkmaid  happens  to  be  in  the  early  stages  of  some 
infectious  disease  such  as  typhoid  fever,  cholera,  scarlet 
fever,  or  diphtheria,  and  is  not  personally  very  cleanly, 
fresh  infectious  materials  (faecal,  epidermal  or  mucous) 
may  easily  obtain  access  to  hands  or  fingers,  and  in  the 
process  of  milking  be  readily  communicated  to  the  milk. 
It  is  unfortunately  a  not  unknown  practice  among  milkers, 
in  America  at  least,  in  order  to  soften  and  clean  the  some- 
times dry  and  dusty  teats  of  the  cow,  to  begin  by  milking 
first  with  one  hand  and  then  with  the  other  into  the  palm 
of  the  free  hand  held  as  a  cup,  and  with  the  milk  so  drawn 
to  bathe  and  soften  the  several  teats  before  formally  begin- 
ning to  milk  into  the  milk  pail.  In  this  case  the  hands  often 
still  drip  milk  for  a  moment  or  two  directly  into  the  pail,  and 
the  opportunity  to  transfer  infectious  matters  from  the  hands 
of  the  milker  into  the  warm,  fresh  milk,  which  is  a  good 
culture  medium  for  many  bacteria,  is  manifest.  Clearly,  no 
person  affected  with  transmissible  disease  should  be  allowed 
to  act  as  a  milker,  for  even  when  no  such  moistening  of 
the  teats  with  milk  as  has  been  described  occurs,  the  mere 
pressure  of  hands  upon  teats,  which  is  a  necessary  part  of 
the  process  of  milking,  may  suffice  to  detach  portions  of 
infectious  material,  possibly  merely  microscopic  in  size,  and 
cause  them  to  fall  into  the  milk  pail. 

In  practice,  however,  this  problem  is  a  very  difficult  one, 
because  it  is  often  nearly  or  quite  impossible  to  detect  the 
presence  of  an  infectious  disease  in  its  earliest  stages.  In 


THE   INFECTION   OF   MILK   BY   MILKMEN          281 

typhoid  fever,  for  example,  it  may  be  a  week  or  even  a 
fortnight  before  the  disease  declares  itself  in  an  unmistak- 
able manner ;  and  it  is  admitted  that  persons  very  fre- 
quently have  this  Disease  not  only  in  a  form  so  mild  that 
some  never  take  to  their  beds  (ambulatory  or  "  walking  " 
cases),  but  that  they  never  even  suspect  that  they  have  so 
serious  a  disease.  It  is  plain,  therefore,  that  legislation, 
even  when  honestly  and  faithfully  obeyed,  is  not  enough. 
Too  oftei}  its  application  would  resemble  the  locking  of  the 
stable  door  after  the  horse  had  been  stolen.  There  is, 
indeed,  only  one  absolute  safeguard  against  the  dangers  of 
infection  from  diseased  milkmen,  and  that  is  the  most  abso- 
lute and  scrupulous  cleanness,  not  only  personal  but,  so  to 
speak,  professional  also.  The  milkers  should  be  thoroughly 
clean,  and  the  operation  of  milking  should  be  conducted 
almost  as  a  surgical  operation  is,  namely,  with  extreme 
cleanliness  and  constant  dread  of  disaster  from  infection. 

What  has  been  said  of  the  possibilities  of  infection  of 
milk  by  the  milker  is  no  less  true  of  all  manipulation  or 
"  handling "  of  milk.  If  at  any  time  milk  is  exposed  to 
infectious  matters  from  the  hands  of  persons  working  over 
it,  or  to  infected  dust  or  epidermal  scales  from  the  cloth- 
ing of  such  persons,  danger  exists.  Several  epidemics  of 
typhoid  fever  have  been  traced  by  the  author  to  persons 
manipulating  or  handling  milk  between  the  producer  and 
the  consumer.  Those  who  desire  to  do  so  may  pursue  this 
subject  in  detail  in  the  published  reports  of  these  cases.1 
It  is  probable  that  diphtheria  and  scarlet  fever  are  more 
or  less  readily  conveyed  in  the  same  way.  If  the  infectious 
materials  of  the  latter  disease,  as  seems  likely,  can  be 
conveyed  in  the  epidermal  scales  during  the  "  peeling  " 
(desquamation)  period,  it  is  easy  to  realize  how  readily  they 
may  find  access  to  milk  either  from  the  skin  of  the  patient 
or  the  clothing  of  a  friend  of  the  patient.  As  regards 

1  See  references  above  to  Springfield,  Somerville,  and  Marlborough  epi- 
demics. 


282         MILK   SUPPLY  AND   THE   PUBLIC   HEALTH 

diphtheria,  the  wonder  is  not  that  it  appears  to  be  some- 
times conveyed  by  milk,  but  that  more  cases  have  not  been 
traced  to  this  source. 

One  of  the  most  objectionable  practices  on  the  part 
of  milk  dealers  in  Boston  is  the  custom,  which  is  rarely 
if  ever  departed  from,  of  tasting  every  large  can  of  milk 
on  its  arrival  in  the  city  This  is  done  to  detect  sour  milk 
and  enable  the  buyer  (or  middleman)  to  protect  himself 
against  the  purchase  of  stale  or  ill-flavored  milk.  The 
"tasting"  consists  in  removing  the  plug,  applying  the 
lips  to  the  can,  and  taking  into  the  mouth,  as  if  for  drink- 
ing, a  small  quantity  of  milk  which  is  usually  not  swallowed 
but  spat  out  again,  generally  upon  the  floor  near  by.  Aside 
from  the  aesthetic  considerations  involved,  it  is  apparent 
that  the  application  to  a  mass  of  milk  of  lips  perhaps  asso- 
ciated with  a  throat  charged  with  the  germs  of  diphtheria 
is  a  most  unsanitary  procedure,  and  one  that  ought  to  be 
strictly  forbidden.  It  is  the  appreciation  of  facts  like  the 
foregoing  that  has  led  to  the  establishment  here  and  there 
of  model  dairies  in  which  all  possible  precautions  are  taken 
to  secure  cleanliness  and  security  against  disease  among 
both  the  workmen  and  cows  composing  the  herd.  To  a 
brief  account  of  these  we  shall  presently  return. 

(b)  We  may  now  briefly  consider  the  principles  which 
should  govern  sanitary  endeavor  to  secure  protection  of 
the  public  health  against  milk  infected  by  the  cow  herself. 
It  is  obvious  that,  inasmuch  as  milk  is  for  the  most  part 
consumed  uncooked  and  comparatively  fresh,  the  opportun- 
ity for  direct  transfer  of  infection  from  cow  to  consumer 
is  easy,  and  therefore  that,  generally  speaking,  diseased 
cows  should  not  be  used  as  sources  of  milk  supply  On 
the  other  hand,  it  does  not  follow  that  a  cow  having  a  some- 
what diseased  liver,  kidney,  or  eye,  may  not  give  normal 
milk ;  and  in  practice  it  is  by  no  means  easy,  at  times,  to 
decide  whether  a  cow  is  diseased  at  all,  or,  if  so,  to  what 
extent ;  or,  finally,  whether  being  herself  probably  some- 


INFECTION   OF   MILK   BY   DISEASED   COWS       283 

what  diseased,  either  temporarily  or  permanently,  her  milk 
is  now,  or  is  likely  to  be,  affected.  The  matter  is  further 
complicated  by  the  fact  that  the  cow  is  a  piece  of  property 
having  a  value  to  her  owner,  who  naturally  objects  to  her 
destruction  or  disqualification,  and  accordingly  gives  their 
fullest  possible  value  to  all  doubts  which  exist  as  to  the 
damage  she  may  do.  Moreover,  veterinary  medical  science 
is  not  so  advanced  as  to  be  in  all  cases  thoroughly  trust- 
worthy in  diagnosis,  so  that  the  whole  subject  is  in  a  very 
unsatisfactory  condition. 

All  parties  interested  agree  that  cows  showing  plainly 
and  obviously  the  physical  signs  of  advanced  disease,  of 
any  serious  sort  whatever,  should  not  be  used  for  milk 
supply.  It  is  only  the  diseases  most  difficult  to  diag- 
nose with  certainty,  and  especially  tuberculosis,  about 
which  there  is  much  serious  contention.  Even  in  this 
case,  where  the  physical  signs  are  pronounced  and  appar- 
ently unmistakable,  there  is  as  a  rule  no  serious  difficulty 
in  securing  the  exclusion  of  the  affected  animals  from 
the  herd  of  milch  cows.  It  is  chiefly  concerning  the  more 
obscure  and  early  cases  that  grave  controversy  arises, 
and  this  has  reached  an  acute  stage  only  since  the  dis- 
covery of  tuberculin  by  Koch,  and  its  recommendation  by 
him  (and  more  recently  by  others)  as  an  almost  infallible 
diagnostic  agent  for  the  detection  of  tuberculosis,  followed 
by  legislative  enactments  looking  to  the  destruction  of 
cattle  and  cows  condemned  by  the  results  of  tuberculin 
tests.  Tuberculin  appears  to  be  a  valuable  reagent  for  the 
detection  of  this  disease,  but  it  is  urged  with  some  force 
that  it  is  not  infallible ;  that  it  is  so  delicate  as  to  detect 
sometimes  trifling  lesions,  perhaps  in  places  where  they 
would  be  very  unlikely  to  do  harm  or  so  limited  as  to  be 
readily  recovered  from  or  checked ;  and  that  it  damages 
normal,  healthy  cows  by  subjecting  their  tissues  to  a 
violent  poison,  if  only  for  a  time.  For  these  and  other 
reasons  the  owners  of  cattle  in  Massachusetts  organized 


284        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

and  secured  the  repeal  of  a  statute  involving  a  compulsory 
tuberculin  test,  and  seriously  interfered  with  the  work  of  the 
State  Cattle  Commission.  This  is  perhaps  not  surprising 
when  we  reflect  that  proof  of  the  complicity  of  milk  in  the 
causation  of  tuberculosis  is  not  very  clear  (see  p.  277); 
and  that  it  is  not  certain  that  tuberculosis  of  inner  organs, 
such  as  may  cause  reaction  under  tuberculin,  and  yet  is 
not  revealed  by  physical  signs,  can  affect  the  milk  unfavor- 
ably. Further  experience  with  tuberculin  may  serve  to 
show  whether  the  original  legislation  or  its  hasty  repeal 
was  in  this  case  the  wiser. 

It  is  not  known  or  generally  believed  that  typhoid  fever 
can  be  communicated  by  the  cow  herself,  either  as  a  victim 
of  that  disease  or  as  having  drunk  water  infected  with  its 
germs.  It  is  a  question  often  asked  during  an  epidemic  of 
typhoid  fever  charged  to  milk,  Can  a  cow  that  has  drunk 
sewage-polluted  water  transmit  the  germs  through  her 
milk  ?  The  answer  is  that,  so  far  as  is  known,  she  cannot 
and  does  not. 

One  of  the  most  startling  discoveries  recently  made  in 
regard  to  infectious  materials  in  milk  is  that  of  Dr.  Stokes 
and  an  associate,  of  Baltimore,  who  investigated  a  curious 
creamy  yellowish  layer,  of  a  slightly  suspicious  appear- 
ance, upon  milk  derived  from  a  dairy  tributary  to  that 
city.  They  found  that  the  yellow  layer  was  largely  com- 
posed of  pus,  and  finally  traced  its  origin  to  a  herd  affected 
with  garget.  They  even  believed  that  they  were  able  to 
trace  the  origin  of  the  epidemic  (which  affected  about 
eighty  cows)  to  a  milkman,  who  had  probably  brought  in 
the  germs  from  another  state  and  by  his  hands  conveyed 
the  culture  from  cow  to  cow.  The  authors  were  led  to  in- 
vestigate examples  of  mixed  milk  from  other  herds,  and 
finally  reached  the  important  conclusion  that  the  mixed  milk 
from  almost  any  herd  usually  contains  more  or  less  pus. 

Scarlet  fever  possibly  arising  from  cows  suffering  with 
that  disease  has  already  been  dealt  with  (pp.  264,  278). 


THE  DANGER   OF  USING   RAW   MILK  285 

The  conclusion  of  the  whole  matter  is  sufficiently  obvi- 
ous. The  consumption  of  raw  milk  is  always  attended 
with  grave  dangers,  partly  from  its  usual  pollution  with 
dirt  and  dung,  and  the  objectionable  fermentations  thus 
provoked,  but  chiefly  from  the  fact  that  milk  supply  is 
an  industry  still  in  a  primitive  state,  and  that  uncooked 
milk  is  liable  to  contain  the  germs  of  various  infectious 
diseases  derived  either  from  the  cow  or  from  those  persons 
who  "  handle  "  the  milk. 

The  remedies  lie  along  the  path  of  progress.  Very 
much  as  modern  sanitary  or  aseptic  surgery  differs  from 
that  which  prevailed  before  the  time  of  Pasteur  and  Lister, 
so  the  sanitary  or  aseptic  milk-supply  industry  of  the  future 
will  differ  from  that  of  to-day  ;  and  precisely  as  successful 
sanitary  surgery  depends  in  the  last  analysis  upon  abso- 
lute cleanness,  so  also  does  the  solution  of  the  problem  of 
successful  sanitary  milk  supply. 

§21.  —  Safeguards  against  Polluted  and  Infected  Milk 

As  long  as  milk  is  consumed  raw  or  uncooked,  there  will 
always  be  danger  in  its  use.  There  is  no  possible  way  in 
which  the  absolute  purity  of  raw  milk  can  ever  be  proved 
or  even  established.  The  most  that  can  be  done  with  raw 
milk  is  to  reduce  the  dangers  of  pollution  and  infection  to 
their  lowest  terms  ;  but  after  all  possible  precautions  have 
been  taken  in  regard  to  the  health  of  the  cow  and  in  re- 
gard to  cleanness  in  the  utensils  employed  and  on  the  part 
of  those  who  "  handle  "  the  milk,  mistakes  may  be  made 
or  accidents  may  happen  by  which  the  milk  shall  be  pol- 
luted or  infected.  It  may  be  best  in  certain  cases  to  take 
the  risks  involved  and  to  use  raw  milk  for  infants  or  inva- 
lids. There  is  some  important  evidence  pointing  in  this 
direction ;  but  after  making  every  allowance  for  such  cases, 
it  still  remains  true  that,  from  the  standpoint  of  sanitary 
science,  raw,  uncooked  milk  is  an  unsafe  food,  and  that 


286        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

whenever  it  is  possible  it  should,  before  it  is  swallowed, 
be  cooked  or  otherwise  treated  so  as  to  destroy  any  disease 
germs  it  may  contain.  Various  methods  have  been  pro- 
posed or  employed  to  this  end,  and  to  a  brief  consideration 
of  the  principles  involved  in  these  we  may  now  pass. 

§22.  —  Sterilization 

This  process  has  long  had  its  prototype  in  domestic 
practice  in  the  custom  of  "  scalding  "  milk,  and  the  experi- 
ence of  generations  has  shown  that  repeated  "scaldings" 
suffice  to  make  milk  "  keep  "  a  long  time.  Bacteriology  has 
shown  the  reason  why,  which  is  simply  that  the  ferments 
or  bacteria  which  swarm  in  milk  soon  cause  it  to  sour  unless 
they  can  be  killed,  by  heating  or  otherwise,  or  hindered 
in  their  activities  by  cold.  The  scalding  process  as  con- 
ducted by  the  housewife  has  to  be  repeated  in  order  to  save 
the  milk  because,  once  milk  cools  down  after  boiling,  fresh 
bacteria,  falling  into  it  from  the  air  or  obtaining  access 
to  it  from  pans  or  dishes  not  absolutely  germ  free,  and 
finding  the  field  clear,  soon  grow  and  multiply  enormously, 
tending  to  bring  about  again  very  soon  the  former  con- 
dition of  a  rich  bacterial  vegetation  in  a  highly  favorable 
soil  or  medium.  The  art  of  sterilization  is  based  on  the 
same  principles,  but  avoids  the  necessity  of  repeated  scald- 
ings  by  careful  prevention  of  fresh  invasions  after  the  origi- 
nal bacterial  population  has  been  destroyed. 

There  is  no  question  as  to  the  efficiency  of  sterilization  of 
milk  by  thorough  boiling  or  scalding,  so  far  as  the  destruc- 
tion of  germ  life  goes,  but  the  process  possesses  certain  im- 
portant disadvantages.  In  the  first  place,  owing  to  the  high 
temperature  used  and  the  time  required,  various  chemical 
changes  are  wrought  by  which  a  peculiar  flavor  or  "  taste  " 
is  produced,  known  as  a  "  cooked  "  taste,  and  this  taste  is 
disliked  by  many  persons  who  enjoy  the  bland  and  character- 
istic flavor  of  raw  milk.  In  the  second  place,  there  is  evi- 


THE   DISINFECTION   OF   MILK  287 

dence  which  cannot  be  disregarded  that  thoroughly  cooked 
or  sterilized  milk  is  not  as  readily  digested  by  some  infants  as 
is  normal  or  even  so-called  "fresh  "  city  milk.  Considera- 
tions of  this  sort  have  led  to  attempts  to  avoid  prolonged 
heating  at  a  high  temperature  by  the  processes  of  "  evap- 
oration," "  pasteurizing,"  condensing  by  cold,  etc.,  to  which 
we  shall  briefly  refer  in  the  following  paragraphs.  For  the 
sanitarian,  however,  the  objections  noted,  while  real  and 
well  worth  avoiding,  do  not  materially  affect  the  great  fact 
that  sterilization  of  milk  is  an  important  sanitary  safeguard. 
Because  many  dislike  the  taste  of,  and  some  do  not  -thrive 
well  when  fed  upon,  sterilized  milk,  it  is  none  the  less  true 
that  by  the  use  of  sterilized  milk  infectious  diseases,  so  far 
as  these  are  conveyed  by  raw  milk,  can  be  altogether 
avoided. 

§  23.  —  Pasteurization 

In  view  of  the  objections  to  scalded  and  sterilized  milk 
which  interfere  with  its  practical  usefulness  by  diminish- 
ing its  popularity  among  adults  and  its  usefulness  for  in- 
fants, various  attempts  have  been  made  to  destroy  the 
germs,  and  especially  any  pathogenic  or  disease-producing 
germs  it  may  contain,  while  yet  preserving  as  much  as  pos- 
sible its  normal  flavor  and  its  digestibility.  The  most  im- 
portant of  these  attempts  is  that  known  as  the  process  of 
"  pasteurizing,"  so  called  in  honor  of  Pasteur.  Pasteur- 
izing consists  in  heating  any  fluid  (milk,  cream,  wort,  etc.) 
to  such  a  temperature  as  has  been  described.  In  the  case 
of  milk  the  temperature  preferred  is  about  158°  to  160°  F., 
and  it  is  claimed  that  this  temperature  maintained  for  twenty 
to  thirty  minutes  suffices  to  kill  all  disease  germs  and  most 
germs  of  fermentation  in  milk,  and  yet  produces  but  slight 
changes  in  its  flavor  or  digestibility.  On  the  other  hand, 
it  is  claimed  by  many  that  its  taste  is  in  fact  somewhat 
altered  and  its  digestibility  impaired,  though  certainly  to  a 
less  extent  than  when  more  heat  is  used.  The  author  some 


288        MILK   SUPPLY   AND   THE   PUBLIC   HEALTH 

years  ago  stated  his  position  in  regard  to  pasteurized  milk 
as.  follows,  and  still  holds  essentially  the  same  views :  — 

"  Most  of  the  milk  sold  in  Boston  is  at  least  twenty-four  hours  old 
when  it  reaches  the  consumer.  Much  of  it  comes  by  rail  from  distant 
parts  of  Massachusetts,  and  even  from  other  states.  The  consumer  is, 
as  a  rule,  totally  ignorant  of  the  place  of  origin  of  the  milk  which  he 
buys,  and  equally  so  of  the  conditions  —  whether  wholesome  or  unwhole- 
some, sanitary  or  unsanitary  —  of  the  farms  on  which  the  milk  is  pro- 
duced. 

"  It  would  be  of  great  advantage  to  consumers  and  producers  alike 
if  the  milk  farms  tributary  to  a  great  city  could  be  visited  and  inspected  ; 
and  it  would  add  materially  to  the  keeping  qualities  of  milk  (and  there- 
fore to  its  economic  value)  if  it  could  be  carefully  pasteurized  before 
beginning  its  journey  to  the  city. 

"Moreover,  inasmuch  as  typhoid  fever  is  often  disseminated  by  milk 
and  as  there  is  reason  to  believe  that  milk  is  a  vehicle  for  some  other  in- 
fectious diseases,  such  as  tuberculosis  and  possibly  scarlet  fever  and 
diphtheria,  pasteurization,  which  is  a  safeguard  against  the  conveyance 
of  such  diseases  by  milk,  commends  itself  to  every  sanitarian. 

"  Pasteurization  also  postpones  the  decomposition  of  milk  and  its 
consequent  stateness  by  destroying  germs  which  produce  souring,  and 
thus  helps  to  keep  it  in  this  respect  nearer  to  the  '  normal '  required  by 
infants." 

§  24.  —  Condensation 

The  condensing  of  milk  when  it  is  effected  by  prolonged 
boiling  under  atmospheric  pressure  is  a  great,  and  probably 
an  absolute,  safeguard  against  infectious  diseases  conveyed 
by  milk.  Such  "condensed"  milk  is,  however,  open  to 
the  same  objections  as  sterilized  milk,  and  probably  in  even 
greater  degree.  Condensed  milk  is,  however,  safe  to  use  so 
far  as  infectious  diseases  are  concerned ;  and  in  spite  of  the 
objections  urged  against,  and  which  certainly  require  it  to 
be  used  intelligently,  it  is  a  valuable  adjunct  to  the  sanitary 
food  supplies  of  mankind.  When  milk  is  condensed  at  a 
lower  temperature  by  the  aid  of  the  vacuum  pan,  as  is 
often  the  case,  it  is  probable  that  the  product  is  almost  if 
not  quite  equally  safe  from  a  sanitary  standpoint,  and  some- 
what less  objectionable  from  the  purely  hygienic  point  of 


CONDENSED  MILK  289 

view.     Such  milk,  less  condensed,  is  sometimes  known  as 
"  evaporated  "  milk,  and  is  highly  valued  by  some. 

An  ingenious  process  proposed  for  condensation  is  that 
in  which  cold  instead  of  heat  is  used  for  condensing,  the 
water  being  removed  from  the  milk  by  freezing.  In  this 
process  advantage  is  taken  of  the  fact  that  water  in  freezing 
tends  to  crystallize  pure,  by  allowing  milk,  from  which  the 
cream  has  been  removed  (separated  or  skimmed  milk),  to 
freeze  over  in  shallow  pans  subjected  to  intense  cold.  The 
thin  skimming  of  ice  constantly  forming  at  the  surface 
is  broken  up  by  rakes,  and  fresh  layers  form ;  these  are 
broken  up  in  their  turn,  and  so  on,  until  the  whole  mass 
becomes  a  magma  of  ice  crystals  and  unfrozen  milk.  The 
mass  is  then  centrifugalized ;  and  the  milk,  thus  readily 
separated  from  the  ice,  is  returned  to  the  pans  for  further 
freezing.  At  last  a  condensation  of  sixty  to  eighty  per  cent 
is  attained,  and  afterward  to  the  thickened  fluid  cream  is 
added  in  proper  proportions,  so  that  when  diluted  with  two, 
three  or  four  times  its  own  volume  of  water,  a  product  is 
said  to  be  obtained  closely  resembling  fresh  milk,  having  no 
"cooked"  odor,  and  keeping  its  digestibility  unimpaired. 
This  process  has  not  yet  been  perfected,  but  it  is  cer- 
tainly ingenious  in  principle. 

§  25. —  Modified  Milk 

The  so-called  "modified"  milk  is  important  rather 
from  the  hygienic  than  the  sanitary  point  of  view,  but 
yet  deserves  mention  and  commendation  inasmuch  as 
its  fundamental  requirement  is  clean,  pure,  sanitary  or 
normal  milk.  This  having  been  secured,  the  process  of 
"  modification  "  consists  in  so  adding  to,  or  subtracting 
from,  its  normal  ingredients  that  it  shall  contain  speci- 
fied amounts  of  sugar,  fat,  salts,  etc.,  such  as  may  be 
desired  for  particular  cases  or  ordered  by  physicians  in 
their  treatment  of  disease  or  other  abnormal  conditions. 


290        MILK   SUPPLY  AND  THE   PUBLIC   HEALTH 

In  connection  with  establishments  supplying  "modified" 
milk,  dairies  of  a  superior  order  are  not  infrequently  main- 
tained, and  to  a  brief  consideration  of  sanitary  dairies  in 
general  we  may  now  proceed. 

§  26.  —  Model  (Sanitary)  Dairies 

With  the  advancement  of  sanitary  science  and  an  appre- 
ciation of  the  sources  of  danger  in  the  milk-supply  indus- 
try, there  have  been  established  here  and  there  dairies  in 
which  every  possible  endeavor  is  made  to  provide,  for 
those  willing  to  pay  for  it,  milk  as  safe  and  as  normal  as 
it  is  possible  to  procure  by  the  use  of  the  most  enlightened 
methods.  One  or  more  of  these  may  generally  be  found 
near  every  large  American  city,  and  they  are  deserving  of 
the  highest  commendation  and  the  fullest  support  from 
sanitarians,  because  they  fill  an  important  place  and  do 
a  most  useful  work,  while  at  the  same  time  they  serve  as 
living,  and  generally  prosperous,  examples  of  proper  sani- 
tary standards  of  practice  in  what  is  still  far  too  com- 
monly a  primitive  industry,  primitively  conducted. 

§  27.  —  The  Cows 

These,  in  model  dairies,  are  carefully  chosen  and  of  good 
breeds.  Care  is  taken  to  ascertain,  as  far  as  possible,  that 
they  are  healthy  and  vigorous,  not  only  by  veterinary 
examinations  when  they  are  added  to  the  herd,  but  by 
similar  examinations  regularly  and  often  repeated. 

§  28.  —  The  Stable,  etc. 

The  stable  is  so  arranged  as  to  have  abundant  space, 
light,  fresh  air  and  quick  and  easy  removal  of  urine  and 
droppings.  The  bedding  is  kept  clean  and  sweet,  food  and 
drink  are  ample  and  carefully  chosen,  the  period  of  lacta- 
tion is  not  unduly  prolonged,  the  cows  are  groomed  very 


MODEL  OR  SANITARY  DAIRIES  291 

much  as  valuable  horses  are,  they  are  protected  to  some 
extent  from  the  irritation  of  insects,  they  are  given  space 
out  of  doors  for  exercise  in  winter,  and  pasturage,  with 
good  water  in  abundance  and  sufficient  shade,  in  summer. 

§  29.  —  The  Milkers 

The  milkers  must  be  of  a  grade  high  enough  to  appre- 
ciate, at  least  in  some  degree,  and  to  be  willing  cheerfully 
to  cooperate  in,  the  general  sanitary  plan.  They  must 
be  willing  to  wash  their  hands  before  beginning  to  milk. 
They  must  in  some  cases  be  ready  to  wear,  while  milking, 
uniforms  of  white,  clean  cloth.  They  must  be  willing, 
before  beginning  to  milk,  to  wash  the  cow's  udder,  if  this 
is  necessary,  or  to  wipe  it  and  the  teats  with  a  clean,  damp 
cloth.  They  must  be  ready  to  decline  to  use  pails,  cans, 
strainers,  etc.,  not  strictly  and  scrupulously  clean.  Above 
all,  they  must  be  ready  to  refrain  from  "  handling "  the 
milk  in  any  way,  if  need  be,  when  in  themselves  or  their 
families  there  is  even  a  suspicion  of  any  infectious  disease, 
such  as  scarlet  fever,  diphtheria,  typhoid  fever  or  the  like. 
These  are  high  qualifications,  but  they  are  not  too  high. 
Persons  working  over  and  about  milk  should  have  quali- 
fications similar  to  those  of  a  trained  nurse,  namely,  intel- 
ligence, faithfulness,  readiness  to  obey  orders,  some 
technical  skill  and  a  high  devotion  to  duty.  Like  the 
nurse,  they  should  be  always  mindful  of  the  fact  that  care- 
lessness, unfaithfulness  or  disobedience  on  their  part  may 
result  in  the  gravest  disaster. 

It  follows,  as  a  matter  of  course,  that  such  service  must 
be  well  paid.  It  follows,  also,  that  for  all  the  care  speci- 
fied, —  and  even  more  is  required  than  is  here  set  down,  — 
for  the  careful  owner  and  manager,  the  veterinary  doctor, 
and  their  various  aids  and  appliances,  large  sums  must  be 
paid.  Hence,  those  who  enjoy  the  benefits  of  such  sanitary 
dairies  must  be  prepared  to  share  the  burdens  of  their 


292        MILK   SUPPLY  AND   THE   PUBLIC   HEALTH 

support.  Milk  sold  from  model  dairies  commands,  and 
deserves  to  command,  a  higher  price  than  that  from  prim- 
itive establishments  carelessly  conducted.  There  is  not 
the  smallest  doubt,  however,  that  impure  milk  is  dear  at 
any  price,  precisely  as  are  impure  water,  impure  air  and 
other  foods  or  necessaries  of  life. 


§  30.  —  The  Outlook  for  Improved  Milk  Supplies 

There  is  a  very  general,  encouraging  and  wholesome  ten- 
dency on  the  part  of  the  public  to  demand  a  better  milk 
supply.  Already  there  are  many  signs  that  the  time  has 
gone  by  when  it  will  be  considered  sufficient  for  a  board 
of  health  to  secure  protection  of  the  public  against  fraud 
due  to  adulteration  of  milk  with  water,  or  falsification,  of 
one  sort  or  another.  It  is  a  curious  commentary  on  the 
subject  that  in  Massachusetts  many  of  the  official  inspec- 
tors of  milk  are  in  no  way  connected  with  the  boards  of 
health  in  their  respective  cities  or  towns.  This,  wherever 
it  exists,  should  be  changed,  so  that  the  sanitary  protec- 
tion of  milk  shall  be,  where  it  belongs,  in  the  hands  of 
those  charged  with  protection  of  the  public  health. 

NOTE.  Many  valuable  suggestions  upon  this  subject  may  be  found 
in  a  paper  by  R.  A.  Pearson,  M.S.,  entitled  "Market  Milk :  a  Plan  for 
its  Improvement."  [Seventeenth  Annual  Report,  Bureau  of  Animal 
Industry,  (1900).] 


CHAPTER  XII 

ON  CERTAIN  UNCOOKED  FOODS  (MEATS,  OYSTERS,  FRUITS, 
VEGETABLES,  ETC.)  AS  VEHICLES  OF  INFECTIOUS  DIS- 
EASE. THE  SANITARY  SIGNIFICANCE  OF  COOKERY 

INFECTED  water  and  infected  milk  are  perhaps  the 
commonest  and  the  most  dangerous  vehicles  of  infectious 
disease.  They  are,  however,  by  no  means  the  only  vehi- 
cles, certain  other  foods,  such  as  uncooked  meat,  oysters 
and  vegetables,  serving  readily  enough  as  the  carriers  of 
infectious  particles.  The  discovery  of  this  fact  was  first 
made  in  the  case  of  uncooked  meat,  the  muscles  of  swine 
having  been  found  in  1860  to  have  served  as  a  vehicle  of 
a  parasitic  worm,  Trichina  spiralis.  Numerous  epidemics 
of  trichinosis  have  been  studied  since  that  time,  and  this 
disease  is  now  well  known  to  be  caused  by  the  consumption 
of  the  uncooked  flesh  of  infected  hogs.  Special  measures 
of  prevention  are  now  established  in  many  countries  against 
this  disease,  but  the  best  preventive  is  the  simplest,  namely, 
thorough  cooking  of  all  such  products  —  pork,  ham,  sau- 
sages and  the  like — as  are  derived  from  hogs. 

§  I .  —  Trichinosis  or  the  Pork-  Worm  Disease 

This  disease,  which  is  characterized  by  intense  inflam- 
mation and  irritation,  with  high  fever,  soreness,  muscular 
paralysis,  dropsical  swellings  and,  in  severe  cases,  death 
in  from  five  to  fifty  days,  is  now  known  to  be  caused  by  a 
minute  cylindrical  worm  barely  visible  to  the  naked  eye, 
and  therefore  entitled  to  be  called  a  micro-organism,  which, 
in  the  larval  state,  inhabits  the  muscles  of  man,  swine,  dogs, 

293 


294         RAW  FOODS  AS  VEHICLES  OF  DISEASE 

cats,  rats,  mice,  rabbits  and  guinea-pigs,  and  many  other 
animals,  and  in  the  mature  state  lives  in  the  intestines  of 
the  same  animals.  The  male  is  much  smaller  than  the 
female,  and  when  mature  measures  only  about  •£$  of  an 
inch  in  length.  The  female  is  stouter  and  longer,  measur- 
ing when  mature  about  ^  of  an  inch.  The  eggs  are  about 
TfW  °f  an  mcn  *n  ^ngth.  The  young  trichinae,  like  young 
tapeworms,  occur  embedded  in  the  muscles  of  the  hog  and 
various  other  animals  and  man ;  but,  unlike  the  young 
tapeworm,  the  young  trichinae  are  so  small  as  to  be  quite 
invisible  to  the  naked  eye,  and  millions  of  them  may  exist 
in  the  flesh  of  a  pig  without  producing  any  unusual  appear- 
ance in  the  meat  sufficient  to  attract  the  attention,  unless 
with  a  microscope.  When  first  introduced  into  pork  or 
human  flesh,  the  little  worms  are  free  and  coiled  up  among 
the  muscular  fibres,  but  after  four  or  five  weeks  they  be- 
come enclosed  in  minute  whitish,  elongated  oval  or  round- 
ish cysts  or  capsules,  due  to  the  inflammation  and  irritation 
that  they  cause  by  feeding  and  living.  After  a  year  or 
more  these  cysts  become  calcified,  and  are  then  visible  to 
the  eye  as  minute  specks  scattered  through  the  muscles. 
When  enclosed  in  the  cyst,  the  worms  become  dormant, 
and  they  may  live  for  years,  and  even  some  time  after  the 
death  of  their  host.  They  can  do  no  further  harm  unless 
swallowed  by  man  or  some  other  animal.  Each  cyst  con- 
tains a  little  slender  worm  about  fa  of  an  inch  long,  coiled 
up  in  two  or  three  turns. 

If  pork  or  other  flesh  containing  these  worms  —  either 
free  or  enclosed  in  cysts  —  be  eaten  by  man,  they  become 
liberated  in  the  stomach,  and,  entering  the  intestine,  attach 
themselves  to  its  soft  lining ;  and  there,  surrounded  with 
abundant  food,  they  grow  very  rapidly  and  become  mature 
in  about  two  days.  Here  the  females  live  long  enough  to 
produce  broods  of  from  five  hundred  to  one  thousand  young 
worms  each.  As  one  ounce  of  pork  sometimes  contains  a 
quarter  of  a  million  or  more  of  the  worms,  it  is  not  surpris- 


TRICHINOSIS   OR  THE   PORK-WORM   DISEASE     295 

ing  that  the  millions  of  adult  worms  and  their  offspring, 
sometimes  resulting  from  a  single  meal  of  raw  swine  flesh, 
should  by  their  presence  produce  great  irritation  and  inflam- 
mation of  the  intestine  and  violent  diarrhoea  and  vomiting, 
which  are  often  the  first  symptoms  in  severe  cases. 

The  young  worms,  almost  as  soon  as  they  are  born, 
begin  to  eat  or  force  their  way  through  the  membranes  of 
the  intestine  into  the  minute  blood-vessels  and  other  organ- 
isms, thus  vastly  increasing  the  irritation.  Eventually  they 
become  diffused  through  the  entire  system,  and  are  found 
most  abundantly  in  the  groups  of  muscles  nearest  the 
abdominal  cavity. 

The  duration  of  the  disease,  like  its  severity,  is  in  direct 
proportion  to  the  number  of  living  trichinae  swallowed,  and 
varies  from  two  weeks  to  three  or  four  months.  Even  in 
many  comparatively  mild  cases  the  suffering  is  intense,  and 
the  recovery  slow  and  tedious.  When  all  the  worms  have 
become  lodged  in  the  muscles  and  enclosed  in  cysts,  the 
direct  symptoms  cease,  and,  if  the  strength  of  the  patient 
has  been  kept  up,  recovery  is  probable. 

Persons  in  robust  health  may  be  able  to  survive  the 
attack  of  half  a  million  or  more  of  these  flesh-worms,  and 
recover ;  but  there  is  a  limit  to  all  human  endurance,  and 
the  numbers  often  contained  in  the  muscles  of  man  or  the 
lower  animals  killed  by  them  are  almost  incredible.  In 
some  very  severe  cases  the  numbers  contained  in  human 
bodies  have  been  estimated  by  reliable  authorities  to  be 
as  great  as  forty  or  sixty  millions. 

The  cysts  containing  trichinae  were  first  observed  in 
human  muscles  in  1822;  but  the  worms  from  similar  cysts 
were  first  named  and  described  by  Owen  in  1835.  They 
were,  however,  only  regarded  as  anatomical  curiosities  of 
no  practical  importance  until  1860,  when  Zenker  proved 
that  they  are  capable  of  producing  the  severe  and  often 
fatal  disease  now  well  known  under  the  name  of  trichinosis, 
but  which  had  been  previously,  as  it  probably  often  is  still, 


296         RAW  FOODS  AS  VEHICLES  OF  DISEASE 

confounded  with  typhoid  fever,  inflammatory  rheumatism, 
or  rheumatic  fever,  poisoning  and  various  other  diseases. 

§  2.  —  Infected  Pork  as  a    Vehicle  of  Trichinosis 

A  few  epidemics  of  trichinosis  may  be  briefly  referred 
to:  at  Hettstadt,  in  1863,  the  flesh  of  one  pig  infected 
135  persons,  20  of  whom  died.  Many  other  similar  epi- 
demics have  occurred  in  Germany.  The  following  may  be 
cited  in  the  United  States:  at  Marion,  la.,  in  1866,  a  man 
named  Bemis  and  eight  members  of  his  family  ate  under- 
done and  raw  ham,  and  were  immediately  taken  sick. 
Three  died,  and  the  others  narrowly  escaped.  Autopsy 
showed  about  100,000  worms  to  a  cubic  inch  of  muscle  in 
one  of  those  who  died.  At  Dubuque,  la.,  two  families 
were  attacked.  In  one,  five  persons  died ;  in  the  other, 
five  or  six.  A  case  is  cited  by  Dr.  Horr  in  this  connection 
in  which  the  mother  of  a  family  ate  of  the  central  under- 
done part  and  took  the  disease,  while  those  who  ate  the 
better  cooked  outside  parts  escaped.  At  Springfield,  Mass., 
February,  1867,  a  man  and  his  family  ate  of  raw  ham,  and 
all  seven  members  were  attacked  more  or  less  severely 
according  to  the  amount  eaten.  A  daughter  died,  and  the 
father  had  a  long  and  very  dangerous  illness.  At  Albany, 
N.  Y.,  in  January,  1869,  two  boys  ate  of  raw  ham,  and 
were  infected.  The  rest  of  the  family  ate  of  the  same 
ham  cooked,  and  escaped.  At  Rome,  N.  Y.,  December, 
1868,  a  man  and  his  family,  nine  persons  in  all,  ate  raw 
smoked  and  dried  sausages.  The  father,  son  and  two 
daughters  died  before  January  15.  The  sausages  and  salt 
pork  were  examined  and  found  to  be  full  of  trichinae,  as 
were  also  the  muscles  of  those  who  died.  In  New  York 
City,  January,  1869,  eight  cases  occurred  in  a  boarding- 
house  from  eating  sausages.  Two  of  the  victims  died  in 
the  New  York  Hospital,  and  others  were  dangerously  sick. 
It  is  interesting  to  note  that  the  physicians  in  two  hospitals 


EPIDEMICS   OF  TRICHINOSIS  297 

mistook  these  cases  at  first  for  typhoid   fever,  and   only 
discovered  their  mistake  after  one  death  had  occurred. 

The  means  of  prevention  in  the  case  of  trichinosis  is 
very  simple,  namely,  thorough  cooking,  and  the  rarity  of 
the  disease  among  people  who  avoid  raw  or  underdone 
swine  flesh  in  any  of  its  varieties  establishes  the  efficacy 
of  the  remedy.1 

§  3.  —  The  Question  of  Infection  by  Tuberculous  Meat 

Of  late  years  there  has  been  widespread  interest  in  the 
question  of  tuberculous  meat.  There  is  very  little  doubt 
that  the  germs  of  tuberculosis  frequently  occur  in  the 
muscles  of  cattle,  cows,  calves  and  other  animals,  and  the 
possibility  of  their  surviving  the  ordinary  operations  of 
cookery  must  be  allowed  unless  these  operations  are 
thorough.  In  Germany,  and  to  some  extent  in  other  coun- 
tries, inspectors  are  employed  to  prevent  the  sale  of  meat 
obviously  tuberculous.  There  are  very  few  facts  available, 
however,  as  to  the  precise  dangers  of  such  meat,  and  it  is 
difficult  to  resist  the  belief  that  excepting  in  the  use  of 
underdone  infected  meat  there  is  little  danger  of  infection 
by  tuberculosis  from  this  source. 

§  4.  —  Raw  Oysters  as  a  Vehicle  of  Infectious  Disease 

The  possibility  of  infection  by  raw  oysters  grown  in 
sewage-polluted  waters  had  been  recognized  by  sanitarians, 
but  not  much  emphasized,  previous  to  1894.  In  that  year, 
however,  the  attention  not  only  of  sanitarians  but  of  the 
whole  world  was  drawn  to  the  subject  by  a  remarkable 
epidemic  of  typhoid  fever  among  certain  students  of 
Wesleyan  University,  in  Middletown,  Connecticut,  who  had 
attended  a  college  fraternity  banquet  on  the  I2th  of  October, 
and  had  there  eaten  raw  oysters  which  were  afterward 

1  §  I  and  §  2  are  summarized  from  a  Report  prepared  by  Professor  A.  E. 
Verrill  of  Yale  University  for  the  State  Board  of  Agriculture  of  Connecticut. 


298         RAW  FOODS  AS  VEHICLES   OF  DISEASE 

proved  to  have  been  derived  from  sewage-polluted  and 
probably  typhoid-infected  oyster-beds.  A  careful  investi- 
gation was  made  at  the  time  by  Dr.  H.  W.  Conn,  Professor 
of  Biology  in  Wesleyan  University  on  behalf  of  the  State 
Board  of  Health  of  Connecticut,  whose  report  may  be 
found  in  the  Seventeenth  Annual  Report  of  the  State 
Board  of  Health  of  Connecticut  for  1894,  and  also  as 
Appendix  Number  Three  of  the  Supplement  to  the  twenty- 
fourth  Annual  Report  of  the  Medical  Officer  of  the  Local 
Government  Board  for  1894-1895,  entitled  "  Oyster  Culture 
in  Relation  to  Disease,"  p.  152.  London,  1896.  This 
epidemic  was  so  remarkable,  so  ably  investigated  by  Pro- 
fessor Conn,  and  forms  so  complete  a  demonstration  of  the 
efficiency  of  raw  oysters  as  vehicles  of  disease,  that  no 
apology  need  be  made  for  giving  a  somewhat  extended  ab- 
stract of  the  original  paper.  The  author  says  very  truly  :  — 

"  A  more  typical  example  of  an  outbreak  of  typhoid  due  to  a  single 
source  of  infection  has  hardly  been  found  in  the  history  of  medicine,  and 
the  example  furnishes  a  demonstration  of  a  new  source  of  danger  for 
this  disease. 

"The  use  of  raw  oysters  has  before  been  suggested  as  a  possible 
source  of  the  spread  of  the  disease.  The  readiness  with  which  these 
absorb  water,  and  the  fact  that  they  not  infrequently  lie  in  positions 
where  contamination  with  sewage  appears  to  be  possible,  has  led  to 
their  being  suspected  in  several  cases.  It  has  hitherto,  however,  not 
been  possible  to  trace  any  distinct  epidemic  to  them  with  anything  like 
demonstrative  evidence.  The  conditions  which  have  occurred  at  Wes- 
leyan have,  however,  been  exceptionally  well  adapted  to  point  out  this 
connection.  Indeed,  if  one  had  planned  beforehand  a  series  of  experi- 
ments designed  to  prove  the  possibility  of  oysters  as  distributing  typhoid, 
it  would  hardly  have  been  possible  to  have  devised  a  more  satisfactory 
series  of  conditions  than  those  which  have  obtained  in  this  outbreak  at 
Wesleyan." 

§  5. — An  Epidemic  of  Typhoid  Fever  traced  to  Infected 

Oysters. 

About  October  20,  1894,  several  students  were  seized 
with  a  mild  form  of  sickness  accompanied  by  slight  fever, 


A  NOTABLE   EPIDEMIC   OF   TYPHOID   FEVER     299 

which  was  not  at  first  regarded  as  of  much  importance. 
The  cases  increased  in  number,  some  became  more  severe, 
and  after  about  a  week  it  became  evident  that  a  few,  at 
least,  were  suffering  from  typical  typhoid  fever.  New 
cases  continued  to  appear  until,  by  November  i,  there 
were  more  than  twenty.  After  November  i  the  cases 
fell  off,  although  one  appeared  as  late  as  November  9. 
In  all,  there  were  twenty-five  cases  —  twenty-three  of  well- 
defined  typhoid,  of  which  thirteen  were  very  severe.  Four 
of  those  attacked  died. 

Investigation  was  begun  on  November  4.  Suspicion  fell 
at  first  upon  certain  wells  on  the  college  campus,  but  these 
were  excluded,  chiefly  on  the  ground  that  they  were  used 
by  large  numbers  of  townspeople  as  well  as  by  college 
students,  and  that  no  typhoid  had  appeared  among  the 
townspeople. 

No  common  bond  was  at  first  discovered  among  the  vic- 
tims of  the  disease,  some  of  whom  lived  in  different  dormi- 
tories or  club-houses,  and  others  in  private  houses  in  the 
town.  Nor  did  the  persons  affected  board  at  the  same 
tables.  Besides,  Wesleyan  University  is  a  coeducational 
institution,  and  it  was  early  observed  that  the  young 
women  in  the  University  —  about  fifty  in  number  —  were 
wholly  exempt.  Closer  investigation  showed  that,  with 
three  exceptions,  all  the  cases  attacked  belonged  to  three 
fraternities,  and  that  within  these  some  extremely  potent 
source  of  infection  had  been  active.  Attention  was  thus 
concentrated  upon  these  fraternities  and  their  club-houses. 

As  is  usual  in  such  cases,  the  plumbing  was  carefully 
examined,  and  in  two  of  the  three  houses  it  was  found  to  be 
new  and  unexceptionable.  Attention  was  next  fixed  upon 
the  boarding  clubs  within  the  fraternities.  The  water,  the 
ice  and  the  milk  were  all  considered,  but  excluded  as 
sources  of  infection,  from  the  fact  that  they  were  shared  in 
common  by  other  fraternities  or  by  the  townspeople.  Simi- 
lar circumstances  excluded  cream,  ice-cream,  butter,  fruit, 


300          RAW   FOODS   AS  VEHICLES   OF   DISEASE 

and  other  articles  as  probable  sources  of  the  disease.  So 
difficult  and  far-reaching  was  the  inquiry,  that  it  was  even 
suggested  that  certain  new  foot-ball  suits  might  have  been 
infected,  thus  giving  rise  to  the  disease ;  but  only  a  few  of 
the  men  who  had  used  the  suits  were  found  to  be  suffering 
from  the  disease,  while  several  of  the  sick  men  had  never 
touched  them.  There  was  also  no  evidence  of  secondary 
infection  which  could  explain  the  outbreak,  and  particu- 
larly as  there  were  no  early  cases  of  fever  which  could 
have  served  as  the  sources  of  such  secondary  cases.  The 
first  case  appeared  about  October  20,  and  within  a  week 
from  that  time  at  least  fifteen  other  cases  had  made  their 
appearance. 

These  facts,  of  course,  indicated  plainly  a  common  source 
of  infection,  and  made  it  possible  to  believe  that  any  of 
these  was  the  source  of  all  the  others  by  ordinary  contagion. 

Moreover,  there  was  a  very  small  amount  of  typhoid  in 
the  city,  and  — 

"  In  short,  all  the  lines  of  investigation  upon  the  relations  of  the  stu- 
dents, the  conditions  of  their  fraternity  houses,  and  the  tables  at  the 
fraternity  houses  led  to  negative  results,  giving  no  point  of  common 
union  between  the  three  fraternities  in  question,  which  was  not  shared 
equally  by  the  four  other  fraternities  and  the  ladies  in  the  college,  and 
equally  by  the  citizens  in  town." 

A  study  of  the  dates  on  which  the  disease  had  appeared 
threw  suspicion  upon  a  series  of  fraternity  suppers  held  at 
the  society  initiations  of  new  members  upon  the  I2th  of 
October,  and  this  suspicion  was  strengthened  by  the  ex- 
planation which  it  appeared  to  offer  of  one  of  three  cases 
which  had  appeared  among  members  of  the  University  not 
in  any  of  the  three  fraternities.  This  person  had  attended 
the  initiation  banquet  held  by  one  of  these  three  clubs,  but 
had  not  boarded  with  them  either  before  or  afterward.  Ex- 
amination of  the  menu  of  the  banquets  excluded  nearly  all 
articles  of  food,  such  as  water,  ice,  milk  and  cream,  ice- 
cream, fruit  and  salad,  as  possible  sources.  The  celery 


AN   EPIDEMIC  TRACED   TO   A   BANQUET          301 

used  in  the  salad  was  at  first  regarded  as  a  source  of  pos- 
sible danger.  It  had  been  bought  from  different  dealers, 
but  these  dealers  obtained  it  all  from  the  same  grower,  and 
he  had  occasionally  washed  his  celery  in  the  water  of  the 
Connecticut  River  —  a  somewhat  suspicious  circumstance. 
Further  inquiry,  however,  showed  that  the  same  dealer 
supplied  nearly  all  the  celery  used  in  Middletown,  and  had 
consequently  furnished  hundreds  of  families  from  the  same 
source. 

As  a  result  of  the  closest  inquiry  in  regard  to  every  arti- 
cle of  food  or  drink  used  at  the  banquet,  there  were  found 
to  be  only  three  common  to  the  three  suppers ;  namely, 
ham,  a  small  amount  of  fruit,  and  raw  oysters.  The  ham 
was  readily  excluded,  both  because  it  had  been  cooked  and 
because  the  same  dealer  supplied  other  fraternities.  More- 
over, there  was  no  reason  to  suppose  that  it  had  been  con- 
taminated. The  fruit  had  been  shared  by  other  fraternities 
and  by  townspeople,  and  was  therefore  excluded. 

"  As  soon  as  attention  was  turned  to  the  oysters,  however,  the  prob- 
lems began  to  be  solved  at  once.  To  those  engaged  in  the  investiga- 
tion, one  of  the  most  striking  phenomena  was  the  quickness  with  which 
the  puzzling  questions  were  answered  as  soon  as  they  were  studied  in 
the  light  of  the  oysters  as  a  possible  source  of  contamination.  It  was 
found  that  the  ladies  in  the  college  did  not  hold  any  special  supper  on 
the  evening  of  October  12,  nor  eat  raw  oysters,  either  then  or  subse- 
quently. It  was  found  that  of  the  other  four  fraternities,  two  did  not 
use  oysters  at  all  at  the  initiation  suppers ;  one  obtained  oysters  from 
Hartford  dealers,  who  obtained  them  from  a  different  source  than  the 
Middletown  dealers.  The  fourth  used  the  oysters  from  the  same  source 
as  the  fraternities  in  question,  but  had  used  them  cooked,  while  the 
three  fraternities  that  had  suffered  from  typhoid  had  eaten  the  oysters 
on  the  half-shell,  and  consequently  raw.  As  soon  as  it  was  conceived 
that  the  oysters  might  be  the  cause  of  the  trouble,  one  more  of  the  ex- 
ceptions above  mentioned  was  explained,  for  one  of  the  students  belong- 
ing to  another  fraternity,  who  had  suffered  from  a  mild  fever,  stated  that 
at  about  the  time  of  the  initiation  banquets  he  had  eaten  raw  oysters  in 
the  oyster  dealer's  store  in  town.  This,  of  course,  made  it  possible  to 
bring  this  case  within  the  same  source  of  infection. 

"  Inquiry  as  to  the  use  of  the  oysters  in  town  revealed  nothing  which 


302         RAW  FOODS   AS  VEHICLES   OF   DISEASE 

relieved  the  oysters  from  blame.  Quite  a  number  of  families  were  sup- 
plied from  the  same  lot  of  oysters,  but  so  far  as  could  be  learned,  only 
one  family  bought  them  to  eat  raw,  and  this  family  had  subsequently 
moved  from  town  and  had  been  lost  track  of.  Further  facts  concerning 
this  case  will  be  mentioned  later.  The  attendants  in  the  oyster  dealer's 
store  had  probably  eaten  of  the  raw  oysters,  inasmuch  as  they  did  fre- 
quently do  so,  although  they  had  no  definite  recollection  of  this  particu- 
lar lot.  Neither  of  them  had  experienced  any  evil  results.  This,  of 
course,  is  not  surprising,  since  ordinarily  not  much  more  than  ten  per 
cent  of  those  exposed  to  typhoid  fever  suffer  from  the  exposure ;  and 
even  among  the  students  at  the  banquet  not  quite  one  in  four  took  the 
disease.  If  the  people  in  town  who  ate  the  oysters  had  not  generally 
cooked  them  before  eating  them,  a  larger  number  of  cases  would  have 
been  expected." 

The  oysters  at  the  banquets  were  served  on  the  half- 
shell  as  a  course  at  the  beginning  of  the  supper.  Careful 
inquiry  was  made  as  to  how  many  persons  had  actually  par- 
taken of  the  oysters,  and  direct  connection  with  the  oysters 
was  traced  in  all  cases  except  one,  this  one  student  being 
unable  to  remember  that  he  partook  of  them.  He  did,  how- 
ever, attend  one  of  the  banquets.  The  four  who  died  were 
among  those  who  partook  of  the  oysters. 

There  were  also  present  at  the  banquets  a  number  of 
persons  not  students  of  the  college.  Among  them  were  a 
number  of  alumni,  and  five  students  from  Yale  University. 
Reports  were  obtained  from  twenty-four  of  the  alumni  who 
ate  of  the  oysters.  Among  them  were  several  cases  of 
slight  illness,  chills,  diarrhoea,  weakness,  and  the  like  which 
appeared  at  about  the  same  time  that  the  typhoid  appeared 
in  Middletown.  These  may  or  may  not  have  had  some 
connection  with  the  infection.  In  addition,  four  cases  of 
genuine  typhoid  fever  appeared,  most  of  which  had  been 
pronounced  to  be  typhoid  before  there  was  any  knowledge 
of  connection  with  cases  at  Wesleyan  University.  None 
were  severe,  but  all  appeared  simultaneously  with  the  cases 
at  Wesleyan. 

Of  the  five  Yale  students  who  attended  the  banquet,  two 
developed  typhoid  fever,  though  at  a  rather  late  date. 


TYPHOID   FEVER  AND   RAW  OYSTERS  303 

These  facts  demonstrated  that  the  cause  of  the  infection 
was  to  be  sought  in  the  initiation  suppers.  The  cessation 
of  new  cases  at  the  end  of  four  weeks,  and  the  appearance 
of  at  least  six  cases  among  visitors  who  came  to  the  ban- 
quets and  went  away  immediately  afterward,  — 

"are  sufficient  in  themselves  to  indicate  beyond  peradventure  that 
the  initiation  suppers  are  to  be  regarded  as  the  source  of  infection. 
And  when,  further,  it  is  seen  that  only  one  article  of  food  or  drink  was 
used  in  common  by  these  three  societies,  that  was  not  used  equally  by 
the  other  fraternities  in  college  and  by  people  in  town  in  general,  it 
becomes  equally  certain  that  this  one  article  of  food  must  have  been  the 
source  of  infection. 

"  Inquiry  showed  that  the  oysters  in  question  had  been  taken  from 
deeper  water  in  Long  Island  Sound,  and  had  been  brought  [to  Fair 
Haven,  Connecticut]  into  the  mouth  of  a  creek  known  as  Quinnipiac 
River,  and  allowed  to  lie  in  fresh  or  brackish  water  a  day  or  two 
for  fattening  before  they  were  taken  out  of  the  water  and  sent  to  the 
consumers.  During  this  period  of  fattening,  the  oysters  are  known  to 
absorb  fresh  water  and  to  swell  up  and  become  quite  plump.  The 
object  of  this  treatment  is  partly  to  thus  i  fatten  '  the  oysters,  and  partly 
to  wash  them.  Close  to  the  oyster  beds  where  this  fattening  occurs 
are  the  outlets  of  a  number  of  private  sewers.  At  a  distance  of  some 
three  hundred  feet  from  the  beds  where  the  oysters  were  fattened  was 
an  outlet  from  a  private  sewer  from  a  house  in  which  were  two  cases 
of  typhoid  fever.  The  patients  were  a  lady  and  her  daughter.  The 
cases  were  severe,  the  lady  dying  on  the  2ist  of  October,  and  the 
daughter  convalescing  only  after  five  weeks1  sickness.  .  .  .  The  dis- 
tance from  the  outlet  of  the  sewer  to  the  oyster  ground  was  .  .  . 
between  250  and  300  feet.  When  the  grounds  were  surveyed,  it  was 
further  noticed  that  at  the  rising  tide  an  eddy  was  found  to  be  setting 
along  the  shore  from  the  region  of  the  sewer  outlet  up  stream,  in  the 
direction  of  the  oyster  beds.  This  condition  would  plainly  make  it 
possible  for  typhoid  contaminations  from  the  sewer  to  be  carried  to  the 
oysters. 

"  Examination  as  to  the  dates  of  the  cases  of  typhoid  occurring  in 
the  house  on  the  sewer  showed  that  the  two  persons  in  question  were 
taken  sick  at  just  about  the  time  that  the  oysters  sent  to  Middletown 
were  collected.  The  oysters  were  sent  to  Middletown  on  October  10, 
and  the  doctor  was  first  called  to  these  cases  on  October  11.  The 
period  of  incubation  of  typhoid  fever  is  known  to  be  somewhat  variable, 
and  had  certainly  existed  some  time  before  the  doctor  was  called. 


304         RAW   FOODS   AS   VEHICLES   OF   DISEASE 

From  the  fact  that  when  the  doctor  was  called  the  lady  was  suffering 
from  a  severe  chill  and  fever,  it  was  plain  that  the  conditions  were  such 
that  infection  through  the  sewer  might  naturally  have  taken  place  at 
least  for  several  days  prior  to  the  period  of  the  first  visit  of  the  doctor ; 
for  during  this  incubation  period  the  persons  may  appear  well,  and  yet  the 
presence  of  the  typhoid  germs  render  their  excreta  infectious.  Indeed, 
the  danger  might  be  even  greater  at  this  stage  than  subsequently,  since 
as  soon  as  the  disease  is  plainly  indicated  nurses  will  be  pretty  sure  to 
disinfect  the  excreta  and  thus  diminish  the  danger.  This  would  bring 
the  time  of  possibility  of  infection  at  just  about  the  period  when  the 
oysters  sent  to  Middletown  were  collected." 

Special  investigations  made  by  Dr.  Charles  J.  Foote,  of 
the  Yale  Medical  School,  showed  that  typhoid  bacilli 
forced  in  between  the  shells  of  oysters  taken  from  the 
creek  were  found  alive  and  capable  of  growth  at  the  end 
of  forty-eight  hours,  and  — 

"this  is  all  that  is  required  to  account  for  the  outbreak  at  Middle- 
town." 

In  connection  with  an  outbreak  of  typhoid  fever  at 
Amherst  College  at  the  same  time  as  that  of  Wesleyan,  it 
was  learned  that  Fair  Haven  oysters  had  also  been  sent  to 
Amherst.  In  the  latter  institution  a  similar  banquet  was 
held  upon  the  same  evening,  October  12,  at  which  raw 
oysters  were  served,  and  of  six  students  who  afterward 
suffered  from  typhoid  fever  all  but  one  ate  raw  oysters  on 
or  about  that  date.  It  was  not  discovered  whether  or  not 
the  oysters  came  from  the  same  dealer  in  Fair  Haven,  but 
the  suspicion  was  strong  that  such  was  the  fact. 

One  of  the  most  interesting  and  instructive  circum- 
stances connected  with  this  epidemic  remains  to  be  stated. 
A  young  man  whose  home  was  in  Boston,  himself  a  stu- 
dent at  Harvard  University,  came  down  with  typhoid  fever. 
His  case  at  first  seemed  utterly  inexplicable.  It  happened 
that  his  father  was  a  physician  and  for  a  time  no  reason- 
able explanation  could  even  be  thought  of.  It  proved,  how- 
ever, that  about  two  weeks  before  he  fell  ill  he  had  gone 
home  with  a  classmate  whose  family  lived  in  Middletown, 


RAW   SHELLFISH 


305 


and  inquiry  showed  that  he  was  attacked,  after  he  had 
returned  to  his  home  in  Boston,  at  precisely  the  same  time 
as  the  Wesleyan  students,  and  that  he  had  eaten  raw 
oysters  while  in  Middletown.  It  further  appeared  that  the 
oysters  which  he  ate  came  from  the  same  dealer  as  those 
with  which  the  Wesleyan  banquets  were  supplied,  and  that 
he  had,  in  fact,  partaken  of  the  one  lot  which,  as  was 
mentioned  above,  had  been  sold  by  the  Middletown  dealer 
to  a  family  in  Middletown  to  be  eaten  raw. 

§  6.  —  Dangers  of  Infection  from  Raw  Shellfish 

Professor  Conn's  remarks  upon  this  subject  are  instruc- 
tive :  — 

"  It  is  a  very  important  point  to  determine  to  how  great  a  danger 
the  public  is  exposed  from  raw  oysters.  Is  the  distribution  of  typhoid 
by  oysters  a  rare  incident,  or  is  it  a  constant  and  considerable  danger  ? 
These  questions  are  being  everywhere  asked.  Upon  this  matter  at 
present  little  can  be  given  beyond  personal  opinion.  But  the  question 
is  such  a  vital  one  that  a  word  of  personal  opinion  here  may  perhaps 
be  pardoned. 

"  In  the  first  place  it  appears  evident  that  the  public  opinion  at  first 
exaggerated  the  amount  of  the  danger.  The  lot  of  oysters  sent  to 
Wesleyan  was  very  thoroughly  infected,  but  there  is  no  good  evidence 
as  yet  that  other  lots  of  oysters  from  the  same  place  were  equally  dan- 
gerous. The  oysters  sent  to  Amherst  were  probably  also  infected,  but 
these  probably  belonged  to  the  same  lot  as  those  sent  to  Middletown. 
Beyond  this  it  has  as  yet  been  impossible  to  trace  with  certainty  other 
instances  of  typhoid  to  the  Fair  Haven  oysters.  If  it  were  true  that  all 
the  oysters  fattened  at  the  same  place  were  similarly  infected,  it  would 
be  expected  that  quite  a  number  of  cases  of  the  disease  should  be 
traceable  to  the  oysters.  In  New  Haven  especially,  where  the  Fair 
Haven  oysters  are  used  largely,  there  would  presumably  have  been 
found  an  exceptionally  large  amount  of  typhoid.  There  has  been  some 
considerable  typhoid  in  the  city  during  the  months  of  October  and 
November,  and  in  a  few  cases  it  has  been  presumably  traced  to  oysters 
as  shown  elsewhere  in  the  report  of  the  State  Board  of  Health.  But 
there  is  hardly  the  amount  that  would  be  expected  if  the  oysters  were 
all  subject  to  a  contamination  such  as  that  which  affected  those  sent  to 
Middletown.  Indeed,  the  consideration  of  the  conditions  at  the  oystcr- 
x 


306        RAW  FOODS  AS  VEHICLES  OF  DISEASE 

beds  would  lead  to  the  belief  that  the  contamination  of  the  oysters 
would  be  exceptional.  Where  the  oysters  were  placed  near  the  mouth 
of  a  small  sewer,  and  when  this  sewer  came  from  a  house  containing 
typhoid  patients,  the  danger  of  their  contamination  would  be  at  its 
maximum.  Should  they  chance  to  be  placed  near  the  mouth  of  a  large 
city  sewer,  the  danger,  though  a  more  constant  one,  would  be  much  less 
likely  to  produce  any  considerable  contamination  of  a  large  lot  of  oys- 
ters, since  the  typhoid  material  would  be  mixed  with  so  much  water 
as  to  distribute  it  widely  and  in  a  very  dilute  condition.  Only  an 
occasional  oyster  would  thus  be  infected.  At  Fair  Haven,  however, 
when  a  proper  eddy  brought  the  material  from  the  vicinity  of  the  sewer 
toward  the  oysters,  the  chances  were  good  for  the  whole  lot  to  become 
infected.  Perhaps  oysters  might  lie  in  the  same  place  many  a  time 
before  and  after,  and  not  be  injured  thereby,  because  no  eddy  hap- 
pened at  the  right  moment  to  sweep  typhoid  material  in  their  direction. 
The  danger  from  typhoid  infection  is,  therefore,  probably  somewhat 
exceptional,  even  under  the  conditions  existing.  Where  the  oysters  are 
fattened  at  a  distance  from  sewers,  the  danger  practically  disappears  ;  and 
even  where  they  are  open  to  infection  from  large  overflow  of  a  city  sewer, 
the  danger  is  certainly  less  than  in  the  fortunately  exceptional  case  of  the 
oysters  in  the  vicinity  of  a  private  sewer  containing  typhoid  excretions. 
"  The  extent  of  the  danger  will  plainly  depend  very  largely  upon  the 
question  whether  the  typhoid  germs  actually  grow  and  multiply  in  the 
oyster,  or  whether  they  simply  remain  alive  there  for  some  time.  It 
may  be  that  the  oysters  furnish  a  good  culture  ground  for  the  typhoid 
germs,  which  grow  rapidly  when  once  within  the  shell.  This  would,  of 
course,  greatly  increase  the  danger,  for  one  lot  in  a  fattening  bed  might 
infect  others.  On  the  other  hand,  it  may  be  that  the  germs  do  not  grow 
in  the  oysters,  but  that  only  such  individual  bacteria  as  find  entrance 
remain  alive.  In  this  case  the  infectious  material  would  be  found  only 
in  the  juices  in  the  shell  and  adhering  to  the  outside  of  the  shell.  The 
danger  would,  of  course,  be  much  less.  Which  of  these  two  conditions 
represents  the  facts  cannot  at  present  be  stated.  It  is  hoped  that 
experiments  now  in  progress  will  settle  the  matter.  But,  according  to 
either  view,  oysters  may  serve  as  a  means  of  transportation  of  typhoid 
wherever  they  are  fattened  in  the  vicinity  of  sewers  ;  and  wherever  they 
are  placed  in  the  mouths  of  fresh-water  streams  for  this  fattening  process, 
there  will  always  be  the  chance  of  contamination  from  sewage.  Few  of 
the  fresh-water  streams  in  the  vicinity  of  our  large  cities  fail  to  have 
sewage  emptying  into  them.  While,  then,  we  cannot  determine  the 
extent  of  the  danger,  and  while,  in  the  opinion  of  the  writer,  the  dan- 
ger is  not  very  great,  it  must  be  recognized  as  a  danger.  Probably  not 
a  few  of  the  obscure  cases  of  typhoid  which  develop  each  fall  shortly 


SHELLFISH   AS  VEHICLES  OF  INFECTION         307 

after  the  oyster  season  opens,  and  which  cannot  be  traced  to  any  source, 
may  be  due  to  contamination  through  oysters.  It  is,  of  course,  impos- 
sible to  determine  the  truth  of  this  suggestion ;  but  now  that  the  possi- 
bility has  been  pointed  out,  we  may  hope  that  our  health  boards  may,  in 
future  years,  be  able  to  determine  the  real  extent  of  the  danger.  One 
thing  is  sure :  the  public  health  is  placed  in  jeopardy  when  oyster 
dealers,  for  the  sake  of  producing  plumpness,  place  oysters  in  the 
mouths  of  fresh-water  creeks  in  close  proximity  to  sewers.  It  is  hoped 
that  one  result  of  the  epidemic  at  Wesleyan  will  be  to  lead  to  greater 
care  in  this  direction,  both  on  the  part  of  the  oyster  dealers  themselves, 
whose  business  will  certainly  be  greatly  injured  by  the  repetition  of  such 
outbreaks  of  typhoid  as  that  at  Wesleyan,  and  on  the  part  of  our  boards 
of  health,  who  have  in  their  keeping  so  much  of  the  public  weaL" 

§  7.  —  English  and  French  Opinion  in  Regard  to  Dangers 
of  Infections'  Disease  from  Raw  Oysters 

Roused  by  the  remarkable  American  epidemic  which 
has  just  been  described,  the  Local  Government  Board 
instituted  a  careful  investigation  of  the  conditions  under 
which  oysters  and  certain  other  mollusks  are  cultivated 
and  stored  in  Great  Britain ;  and  a  valuable  report,  bring- 
ing the  whole  subject  up  to  date  (1896),  appeared  as  a 
supplement  to  the  report  of  the  medical  officer  of  that 
Board  for  1894-1895.  This  contains  a  report  by  Dr. 
H.  T.  Bulstrode  on  "The  Conditions  under  which  Oysters 
and  Certain  Other  Edible  Mollusks  are  cultivated  and 
stored  along  the  Coast  of  England  and  Wales  "  ;  a  report 
by  Dr.  Klein  on  "  Certain  Bacteriological  Researches,"  in 
connection  with  the  same  subject;  a  copy  of  Professor 
Conn's  report,  already  quoted  in  the  preceding  paragraphs, 
as  well  as  extracts  from  the  "  Proceedings  of  the  Academy 
of  Medicine  of  Paris  relating  to  the  Spread  of  Disease 
through  the  Agency  of  Oysters." 

§  8.  —  The   Contamination  of  Oyster-beds  by  Sewers 

The  concluding  remarks  of  Professor  Conn,  in  his 
report  on  the  "Epidemic  of  Typhoid  Fever  caused  by 


308         RAW   FOODS   AS   VEHICLES   OF  DISEASE 

Raw  Oysters  at  Wesleyan  University,"  indicate,  conclu- 
sively and  in  detail,  the  dangers  to  which  oyster-beds  are 
subjected  when  so  placed  as  to  be  overflowed  and  con- 
taminated by  sewage.  The  English  report  referred  to  in 
the  preceding  paragraph  furnishes  numerous  instances  of 
the  growing  or  storage  of  oysters  under  unsanitary  condi- 
tions; and  those  charged  with  the  conservation  and  pro- 
motion of  the  public  health  should  keep  in  mind  the 
possibility  of  such  contamination,  as  well  as  the  necessity 
for  its  prevention.  No  extensive  investigation  of  this  sub- 
ject has  as  yet  been  made  in  the  United  States ;  but  there 
is  good  reason  to  suspect  that  if  such  examination  should 
be  made,  it  would  reveal,  in  many  cases,  the  existence 
of  unsanitary  conditions  in  connection  with  the  oyster 
industry. 

One  of  the  most  interesting  corollaries  of  the  facts  now 
in  our  possession  in  regard  to  the  dissemination  of  typhoid 
fever  by  oysters  is  the  explanation  which  it  furnishes  of 
certain  so-called  "  sporadic  cases  "  of  typhoid  fever  hitherto 
inexplicable.  Whether  or  not  the  same  facts  will  suffice 
to  account,  in  part,  for  that  excess  of  typhoid  fever  which 
is  characteristic  of  many  American  communities  over  simi- 
lar communities  in  the  Old  World,  is  unknown ;  but  it  is 
difficult  to  resist  the  feeling  that  such  may  be,  to  some 
extent,  the  fact.  The  whole  subject  of  the  dissemination 
of  disease  through  uncooked  foods  requires  further  study 
and  elucidation. 

§  9.  —  Fruits,    Vegetables,  Ice-cream,  etc.,  as   Vehicles  of 
Infectious  Disease 

Inasmuch  as  any  uncooked  food  material  may  be  pol- 
luted, and,  if  eaten  in  this  condition,  may  become  the  source 
of  disease,  it  is  easy  to  see  how  berries,  such  as  straw- 
berries, grown  and  lying  on  earth  which  has  been  fertil- 
ized with  night  soil,  or  mulched  with  infected  manure; 
raspberries,  cherries,  apples,  grapes,  and  similar  fruits; 


POSSIBLE   ORIGIN   OF   SOME   "SPORADIC"   CASES      309 

vegetables,  such  as  lettuce,  celery,  radishes,  onions,  water- 
cress and  the  like,  if  eaten  raw,  or  without  adequate  clean- 
ing, may  readily  convey  the  germs  of  infectious  disease  to 
the  consumer.  There  can  be  little  doubt  that  the  common 
American  practice  of  buying  fruit  at  fruit-stands,  or  from 
passing  venders  on  the  streets  or  in  railway  trains,  may  be 
a  ready  means  for  the  distribution  of  infectious  disease. 
When  we  reflect  that  not  infrequently  the  fruit  shop  is 
also,  to  a  greater  or  less  extent,  the  home  of  the  vender's 
family ;  when  we  reflect  on  the  frequent  picking  over  of 
berries,  cherries,  apples,  and  the  like,  by  persons  whose 
hands  and  whose  personal  habits  may  be  far  from  clean ; 
when  we  add  to  this  the  exposure  of  the  fruit  to  dust  and 
dirt  from  various  sources ;  and  when,  finally,  we  remember 
that  buyers  of  such  fruits  or  vegetables  often  devour  them 
on  the  spot  without  stopping  to  make  sure  that  they  are 
clean,  we  can  readily  see  that  in  such  food  materials  thus 
exposed,  and  eaten  without  having  been  sterilized  by 
cookery,  we  have  a  ready  means  for  the  dissemination  of 
infectious  disease  and  an  explanation  of  "  sporadic  "  cases. 

On  the  other  hand,  it  is  reassuring  to  note  that  certain 
fruits,  such  as  oranges  and  bananas,  although  usually  eaten 
raw,  are  effectively  protected  by  their  skins,  which  are 
invariably  rejected,  leaving  only  the  clean  and  sterile 
interior  to  be  eaten. 

As  to  sugared  figs,  dates,  and  similar  preserved  fruits, 
while  there  is  probably  less  danger,  it  must  not  be  over- 
looked that  if  these  have  been  prepared  by  unclean  or 
infected  persons,  they  also  may  become  vehicles  of  the 
germs  of  infectious  disease. 

The  dangers  connected  with  the  consumption  of  ices  and 
ice-creams  are  probably  real.  After  making  all  possible 
allowance  for  those  cases  of  ice-cream  poisoning  which  may 
have  been  due  to  metallic  poisons  derived  from  the  freezer 
or  other  utensils,  it  must  be  admitted  that  the  ice,  the 
water,  and  especially  the  milk,  used  are  liable  to  be  sources 


310        RAW  FOODS  AS  VEHICLES  OF  DISEASE 

of  disease  in  ices  or  ice-creams.  Bacteriological  examina- 
tions of  ice-cream  are  by  no  means  reassuring,  large  num- 
bers of  germs  often  being  present,  and  ices  and  ice-cream 
may  conceivably  do  harm  either  by  the  bacteria  which  they 
contain  or  by  their  chemical  products  (toxines  or  ptomaines). 

§  10.  —  The  Sanitary  Significance  of  Cookery 

Nothing  is  more  certain  in  sanitary  science  than  that 
cookery,  which  by  the  use  of  heat  destroys  parasites 
(including  bacteria),  is  of  the  very  highest  hygienic  value. 
If  we  may  accept  Charles  Lamb's  celebrated  account  of  its 
discovery  and  general  introduction,  these  were  due  more 
to  the  appetizing  flavors  which  it  develops  than  to  anything 
else.  To-day,  however,  the  sanitarian  recognizes  that  im- 
portant as  are  the  flavors  developed  by  cooking  in  stimu- 
lating appetite  and  creating  or  arousing  a  keen  relish  for 
food,  they  are  of  but  minor  consequence  as  compared  with 
the  importance  of  freeing  roast  pig  and  similar  foods  from 
possible  parasites  such  as  Trichina,  or  tapeworms  (p.  118). 
Writers  on  the  physiology  of  cookery  do  not  usually  dwell 
sufficiently  upon  this  aspect  of  the  subject.  They  are 
accustomed,  rather,  to  point  to  the  greater  digestibility  of 
starches,  meats,  and  fats  when  these  are  properly  prepared 
for  internal  digestion  by  the  external  digestion  (cookery) 
of  the  kitchen.  They  emphasize  also  the  improved  flavors 
developed,  which  arouse  the  appetite  and  stimulate  the 
powers  of  digestion.  These  are  unquestionably  of  great 
importance ;  but  probably  far  more  important  in  the  history 
of  the  race  has  been  the  fact  that  by  fire  food  is  largely 
purified  from  living  parasites  and  other  agents  of  infection. 


CHAPTER  XIII 

ON    THE    PREVENTION    AND    INHIBITION    OF    INFECTION,    DE- 
COMPOSITION AND   DECAY.       ASEPSIS  AND   ANTISEPSIS. 

§  I.  — Asepsis,  or  the  Prevention  of  Infection  by  Exclusion 

IT  has  already  been  stated  in  a  previous  chapter  that 
for  the  genesis  of  infectious  disease  two  factors  at  least  are 
necessary ;  namely,  first,  an  infectious  substance,  material 
or  element,  ordinarily  a  micro-organism;  and,  second,  a 
susceptible  subject.  In  other  words,  a  state  of  infectious 
disease  in  an  organism,  whether  plant  or  animal,  depends 
upon  an  infectious  element  proceeding  from  the  environ- 
ment and  also  upon  a  special  condition  of  the  organism 
such  that  it  is  capable  of  being  successfully  acted  upon  or 
interfered  with  by  the  infectious  element  or  its  products. 
Infectious  disease  in  its  transmission  or  distribution  thus 
represents  one  phase  of  the  eternal  struggle  for  existence, 
or  that  interplay  with  the  environment  which  is  the  funda- 
mental phenomenon  of  life  (cf.  p.  63).  On  the  part  of  the 
organism  attacked,  it  represents  a  phase  in  that  continuous 
attempt  at  adjustment  of  internal  to  external  relations 
which  has  been  well  defined  as  a  leading  characteristic  of 
the  life  process  (cf .  p.  69).  It  will  not  do  to  assume  that 
the  cause  of  disease  resides  either  in  the  infectious  element 
alone  or  chiefly,  or  in  the  organism  attacked  alone  or 
chiefly.  The  true  cause  of  disease  is  to  be  found  in  the 
cooperation  of  both  factors,  namely,  the  infectious  element 
and  the  susceptible  organism.  It  cannot  be  denied,  how- 
ever, that  in  the  common,  everyday  use  of  the  word  "cause," 
it  is  the  aggressor  rather  than  the  defendant  which  is  prop- 

3" 


312    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

erly  cited  to  appear ;  and  nothing  is  clearer  than  the  fact 
that  if  the  infectious  element  can  be  successfully  excluded 
or  warded  off,  the  disease,  which  might  otherwise  appear 
as  the  result  of  its  entrance  or  attack,  can  be  avoided. 

Modern  surgery  is  the  best  possible  example  of  the 
beneficent  results  of  this  kind  of  procedure.  Before  any 
serious  operation  upon  the  internal  portions  of  the  organ- 
ism is,  to-day,  undertaken  the  parts  upon  which  the  incision 
is  to  be  made  are  carefully  cleaned,  and  even  sterilized, 
with  the  sole  object  of  excluding  putrefactive  or  morbific 
germs.  All  knives  and  other  instruments,  all  ligatures  and 
similar  appliances,  are  carefully  freed  by  heat  or  by  disin- 
fectants from  possible  septic,  putrefactive  or  infectious 
elements,  and  the  most  extraordinary  pains  are  taken  to 
exclude  as  completely  as  possible  all  micro-organisms. 
Surgery  of  this  kind  is  rightly  called  "aseptic,"  and 
although  doubtless  in  many  cases  it  is  not  absolutely  suc- 
cessful in  excluding  every  micro-organism,  it  is  neverthe- 
less sufficiently  so  in  the  great  majority  of  cases  to  insure 
the  wonderful  success  which  attends  modern  surgical 
operations. 

We  have  referred  to  aseptic  surgery  in  an  earlier  chapter 
as  "  sanitary  "  surgery,  and  the  justice  of  this  appellation 
will  be  perceived  when  we  point  out  that  precisely  the 
same  kind  of  exclusion  is  sought  for  in  the  larger  pro- 
cedures of  the  public  health,  as  when,  for  example,  a  water 
supply  is  freed  from  the  germs  of  infectious  disease  by 
exclusion.  When  pains  are  taken  to  see  to  it  that  no  cases 
of  infectious  disease  shall  be  allowed  to  infect  a  particular 
watershed,  we  are  acting  upon  principles  precisely  similar 
to  those  invoked  in  a  modern  "  aseptic  "  surgical  operation, 
and  there  can  be  no  doubt  that  the  procedure  is  at  least 
as  reasonable  and  as  desirable  in  the  case  of  the  water 
supply,  which  affects  thousands,  as  in  the  case  of  a  single 
patient  undergoing  a  surgical  operation.  The  life  of  the 
community  may,  in  theory  at  least,  and  to  a  large  extent 


ASEPSIS   AND   ANTISEPSIS  313 

in  practice,  be  protected  by  the  mere  exclusion  of  patho- 
genic micro-organisms  from  water  supplies,  milk  supplies 
and  air  supplies. 

§  2.  —  Quarantine  and  Isolation 

It  is  the  recognition  of  facts  like  these  which  have  led 
even  uncivilized  peoples  instinctively  to  the  endeavor  to 
ward  off  disease  in  a  wholesale  fashion  by  the  exclusion 
of  suspected  persons,  or  by  their  detention  at  the  frontier, 
of  a  particular  country  until  time  shall  have  demonstrated 
that  they  are  or  are  not  vehicles  of  infection.  The  word 
"  quarantine  "  is  in  itself  a  witness  to  the  custom  of  deten- 
_tion,  which  in  former  times  was  sometimes  forty  days. 

£  Modern  sanitary  science  has  tended  to  show  that  quaran- 
tine, or  the  attempt  of  communities  to  protect  themselves 
by  the  exclusion  of  human  beings  and  merchandise  which 
are  possible  vehicles  of  infectious  disease,  is  only  a  rude 
and  generally  imperfect  method  of  exclusion.  There  can 
be  no  question,  however,  as  to  the  legitimacy  of  the 
fundamental  principle  involved. 

,  Of  late  years,  and  with  the  increasing  evidence  of  the 
difficulty  of  securing  freedom  from  infectious  disease  by 
exclusion,  the  practice  of  quarantine,  at  least  in  the  old 
form  and  on  the  frontier,  has  fallen  into  comparative  dis- 
repute. A  modified  form  of  quarantine,  has,  however, 
come  into  wider  usage,  namely,  what  is  now  known  as 
"isolation."  Isolation  is  essentially  local  -or  sporadic 
quarantine,  in  which  the  person  or  merchandise  suspected 
of  being  a  vehicle  of  disease  is  separated  or  isolated, 
wherever  found,  or  in  a  convenient  neighboring  locality, 
from  all  other  persons  or  articles  of  merchandise  until 
the  danger  shall  have  passed,  or  the  infectious  materials 
have  been  destroyed.  )•  It  is  found  practically  that  this  - 
method  of  local  or  sporadic  quarantine  in  highly  civilized 
countries  is  more  perfect  and  successful,  on  the  whole, 
than  the  wholesale  or  frontier  quarantine;  while  it  inter- 


314    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

feres  far  less  with  the  ordinary  conduct  of  commercial 
life,  and  is  therefore  less  subject  to  the  usual  tempta- 
tions to  elude,  evade  or  disobey  quarantine  regulations. 
Everything  depends,  however,  in  the  prevention  of  in- 
fection by  exclusion,  precisely  as  is  the  case  in  sanitary 
surgery,  upon  the  thoroughness  with  which  the  exclusion 
is  carried  ouL~7Practically  this  means,  in  particular  cases, 
that  it  deplHiHs  upon  the  thoroughness  with  which  the 
law  is  enforced  and  obeyed,  and  neither  quarantine  nor 
isolation  can  be  successfully  carried  out  in  any  country 
or  in  any  community  in  which  the  police  regulations  are 
ignored  or  disobeyed.  Hence  it  has  come  to  pass  that  the 
less  civilized  nations  still  prefer  to  depend  mainly  upon 
frontier  quarantine,  where  it  is  possible  to  keep  up  at  least 
the  form  of  prevention  by  exclusion ;  whereas,  if  once  the 
infectious  materials  should  be  introduced,  it  is  realized 
that  little  or  no  dependence  could  be  placed  upon  the 
thoroughness  of  local  or  sporadic  isolation.  On  the  other 
hand,  the  more  highly  civilized  nations,  which  have  confi- 
dence in  their  ability  to  quarantine  locally,  i.e.  to  isolate 
sporadic  cases  or  even  infected  communities,  lay  compara- 
tively little  stress  upon  frontier  quarantine,  well  knowing 
how  difficult  and  often  impossible  it  is  to  make  it  thorough, 
preferring  rather  to  depend  upon  such  local  quarantine  by 
isolation  of  sporadic  cases  as  may  become  necessary. 

There  is  still  considerable  difference  of  opinion  as  to  the 
value  of  quarantine  regulations.  No  one  can  doubt  that  in 
special  cases,  such  as  the  arrival  of  ships  in  well-guarded 
harbors,  it  is  still  possible  to  effect  important  measures  of 
protection  by  the  exclusion  of  infection  through  quarantine 
control.  This  is  particularly  true  of  many  cities  and  har- 
bors of  the  United  States  to  which  vessels  may  come  after 
long  periods  at  sea,  bringing  unmistakable  evidence  of  infec- 
tious disease.  Such  vessels  may  well  be,  and  often  are, 
detained  in  quarantine  in  New  York,  or  Boston,  or  San 
Francisco,  with  immense  advantage  to  the  public  health. 


PREVENTION   BY   QUARANTINE  AND   ISOLATION      315 

But,  on  the  other  hand,  such  attempts  at  exclusion  by 
quarantine  regulations  as  have  been  frequently  instituted 
along  the  sparsely  inhabited  frontiers  of  our  Southern 
states,  during  periods  of  alarm  because  of  yellow  fever, 
are  probably  comparatively  ineffective. 

§  3.  —  Immunity,  or  tlie  Prevention  of  Infection  by  Insus- 
ceptibility 

Nothing  is  clearer  than  the  fact  that  the  normal  organ- 
ism possesses  marked  powers  of  resistance  to  the  invasions 
of  infectious  disease,  or  that  some  individuals  offer  more 
resistance  than  others.  Such  variations  in  resistance  may 
be  described  as  variations  in  susceptibility,  and  total  insus- 
ceptibility, or  perfect  resistance  to  infectious  disease,  is 
spoken  of  as  immunity.  The  term  "  immunity"  is,  however, 
generally  limited  to  specific  immunity,  i.e.  immunity  to  a 
particular  disease  or  diseases.  Obviously,  if  general  im- 
munity to  infectious  disease  could  be  brought  about,  little 
attention  would  need  to  be  paid  either  to  the  vehicles  of 
infection  or  to  the  infectious  elements  themselves.  Theo- 
retically and  practically,  the  production  of  immunity  in 
normal  organisms,  whether  plant  or  animal,  is  the  goal  of 
sanitary  science,  so  far  at  least  as  infectious  diseases  are 
concerned.  At  present,  however,  this  goal  is  not  even  in 
sight,  so  that  strenuous  efforts  must  still  be  made,  and  prob- 
ably for  a  long  time  to  come,  to  prevent  infectious  disease 
by  the  control  or  destruction  of  infectious  elements  in  the 
environment,  and  by  their  exclusion  from  possibly  suscep- 
tible individuals. 

Meantime,  although  the  goal  is  not  in  sight,  some  steps 
toward  it  have  been  taken,  at  least  in  the  case  of  certain 
diseases ;  and  although  these  have  been  dwelt  upon  already 
(p.  75),  we  may  refer  to  them  again  at  this  point.  The  first 
progress  consciously  made  in  this  direction  was  that  in- 
volved in  the  process  known  as  inoculation  for  small-pox, 


316    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

and  to  a  consideration  of  this  process,  with  its  natural 
corollaries,  vaccination  and  serum  therapy,  we  shall  im- 
mediately return.  At  this  point  we  may  observe,  in  pass- 
ing, that  insusceptibility  appears  to  be  in  many  cases  very 
largely  a  matter  of  physiological  vigor  and  robust  living. 
There  can  be  but  little  question  that  individuals  of  strong 
constitution,  well  fed,  well  housed,  well  trained  physically, 
and  free  from  corroding  care,  anxiety,  trouble,  overwork, 
want  of  sleep  and  similar  depressing  influences  are 
materially  strengthened  in  their  powers  of  resistance  to 
disease.  These  matters  are  of  fundamental  importance, 
therefore,  to  the  public  health,  and  the  student  of  sanitary 
science  must  always  bear  in  mind  the  significance  for 
the  public  health  of  conditions  favoring  the  most  perfect 
operation  of  the  animal  organism.  Overcrowding,  over- 
work, overexcitement,  underfeeding,  undersleeping,  under- 
exercise  —  in  short,  all  conditions  which  tend  to  remove 
the  organism  from  the  normal  in  physical  vigor  —  tend  to 
the  diminution  of  vital  resistance  and  to  the  increase  of 
susceptibility  to  disease.  They  are  to  be  avoided  as  un- 
wholesome and  unsanitary,  while  normal,  happy,  vigorous, 
physical  life  is  to  be  encouraged  as  probably  the  most 
fundamental  and  far-reaching  of  all  sanitary  measures 
tending  to  promote  the  public  health. 

§  4.  —  Insusceptibility  Artificially  produced  by  Inoculation 

One  of  the  earliest  attempts,  if  not  the  earliest,  to  influ- 
ence directly  the  degree  of  susceptibility  of  the  organism 
to  an  infectious  disease  was  that  of  inoculation  for  small- 
pox.1 This  disease,  like  other  well-known  infectious  dis- 
eases, such  as  the  plague,  appears  to  have  been  imported  into 
Europe  from  Asia,  where  it  had  been  known  from  remote 
antiquity.  Early  in  the  eighteenth  century,  and  chiefly 
through  letters  of  Lady  Mary  Wortley  Montagu,  it  became 

1  This  subject  has  already  been  discussed  at  length  above  (pp.  76-80). 


PREVENTION  BY   INSUSCEPTIBILITY  317 

known  that  a  certain  advantage  to  any  individual  liable  to 
exposure  to  small-pox  might  be  derived  by  direct  inocula- 
tion with  the  virus  of  the  disease  intentionally  introduced 
at  a  time  when  the  subject  was  in  good  health,  so  that  he 
should  have  the  disease  under  the  most  favorable  circum- 
stances, rather  than  possibly  at  some  time  when  conditions 
might  be  less  favorable.  This  method  was  known  and 
practised  in  the  East,  or  at  least  in  Turkey,  at  this  time ;  and 
chiefly  through  the  letters  from  Constantinople  of  Lady 
Montagu  it  became  known  in,  and  was  speedily  introduced 
into,  England  and  America.  There  is  no  reason  to  doubt 
that  such  inoculations  tended  in  a  marked  degree  to  bring 
about  individual  insusceptibility  and  immunity;  and  it  is 
certain  that  under  its  influence  the  fatality  of  small-pox  was 
lessened,  while  only  a  small  percentage  of  those  inoculated 
perished  from  the  disease. 

The  objections  to  inoculation,  however,  were  great;  for 
although  usually  those  inoculated  had  the  disease  in  a 
relatively  mild  form,  occasionally  the  severest  symptoms 
ensued,  and  disfiguration  was  not  uncommon.  Moreover,  as 
the  method  was  essentially  one  of  cultivation  of  the  disease, 
those  inoculated  became  veritable  centres  of  infection ;  and 
it  is  said  that,  on  the  whole,  the  practice  tended  to  spread 
the  disease  and,  while  benefiting  individual  cases,  tended  to 
increase  the  general  mortality.  It  was  gradually  displaced 
after  Jenner's  discovery  of  vaccination  by  that  far  safer 
method  of  producing  insusceptibility,  and  in  1840  an  act 
of  Parliament  was  passed  rendering  small-pox  inoculation 
unlawful  in  England. 

The  student  of  preventive  medicine  and  immunity  may 
find  in  the  history  of  small-pox  inoculation  many  valuable 
lessons,  of  which  the  most  obvious  and  important  is  the  fact 
that  the  normal  healthy  organism  in  its  best  estate  is  often 
able  to  resist  the  onslaughts  of  even  very  virulent  diseases, 
directly  and  intentionally  introduced  into  the  body.  Noth- 
ing could  testify  more  clearly  to  the  fundamental  impor- 


318    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

tance  in  sanitary  science  of  personal  hygiene,  and  the 
immense  importance  of  keeping  the  body  in  the  best  pos- 
sible physiological  condition.  Herein,  no  doubt,  lies  the 
key  to  the  explanation  of  the  fact  that  in  any  epidemic, 
however  widespread,  a  large  percentage  of  persons  escape 
the  disease  altogether,  while  another  large  percentage  suf- 
fer from  it  but  little. 

On  the  other  hand,  the  history  of  inoculation  teaches 
that  even  under  conditions  apparently  the  most  favorable, 
a  few  who  might  be  supposed  to  be  naturally  exempt,  owing 
to  abundant  vitality,  do,  nevertheless,  suffer  in  an  almost 
inexplicable  fashion.  While,  therefore,  it  is  plainly  the 
duty  of  the  sanitarian  to  do  everything  in  his  power  to  pro- 
mote the  practice  of  personal  hygiene,  it  is  no  less  his 
bounden  duty  to  seek  at  the  same  time  to  remove  the  spe- 
cific causes  of  disease  from  the  environment.  The  art  of 
hygiene  is,  and  probably  always  will  be,  twofold :  on  the 
one  hand,  the  creation  or  promotion  of  personal  insuscepti- 
bility; and,  on  the  other,  the  control  or  abatement  of  the 
specific  inciters  of  disease :  this  double  duty  consisting, 
on  the  one  hand,  of  reenforcement  of  the  organism,  and 
on  the  other,  of  mastery  of  the  environment. 

§  5.  —  Insusceptibility  Artificially  produced  by  that  Variety 
of  Inoculation  known  as    Vaccination 

By  far  the  most  interesting  and  important  attempt  to 
bring  about  insusceptibility  to  an  infectious  disease  is  vac- 
cination for  small-pox *  —  an  art  now  well  known  and  fully 
tested  all  over  the  world.  Introduced  by  Jenner  at  the 
end  of  the  eighteenth  century,  and  improved  and  ex- 
tended by  his  successors,  vaccination  is  to-day  the  princi- 
pal weapon  employed  by  the  human  race  in  its  warfare 
with  one  of  the  most  loathsome,  and  formerly  one  of  the 

1  This  subject  has  already  been  discussed  briefly  in  another  connection 
(p.  80). 


PREVENTION   BY   INSUSCEPTIBILITY  319 

most  dreaded,  of  all  infectious  diseases.  Its  practice  is 
justified  not  only  by  experience  but  also  by  experiment, 
for  it  has  been  conclusively  and  repeatedly  proved  by 
actual  experiment  that  persons  thoroughly  vaccinated  are 
for  a  longer  or  shorter  time  insusceptible  to  successful 
small-pox  inoculation.  (See  e.g.,  Report,  Boston  Board 
of  Health,  for  1802.) 

The  theory  of  vaccination  depends  simply  upon  the  fact 
that  comparative  immunity  appears  to  be  produced  in  a 
vaccinated  organism  by  causing  it  to  undergo  what  is  prob- 
ably a  very  mild  form  of  small-pox,  or,  possibly,  a  cognate 
and  much  milder  disease  —  namely,  small-pox  of  the  cow, 
or  "cow-pox."  Moreover,  it  is  the  usual  custom  to  inocu- 
late persons  whom  it  is  desired  to  protect  from  small-pox 
with  vaccine  virus,  as  in  the  case  of  inoculation  proper, 
when  they  are  in  good  condition  and  well  fitted  to  resist 
an  attack  of  disease. 

Vaccination  does  not  differ  much  in  principle  from  the 
earlier  art  of  inoculation ;  and  although  it  is  not  clear  in 
either  case  how,  precisely,  a  mild  attack  of  the  disease 
against  which  defence  is  sought,  or  of  a  related  or  modified 
form  of  the  disease,  such  as  cow-pox,  confers  immunity, 
various  theories  concerning  this  acquirement  are  extant, 
none  of  which  can  be  said  to  be  entirely  satisfactory. 
The  best  is,  perhaps,  that  of  the  reaction  of  the  organism 
in  the  production  of  defensive  antidotes  to  the  specific 
virus,  a  matter  which  will  be  more  fully  explained  in  the 
next  section. 

There  is  no  doubt  that  comparative  freedom  of  the  most 
highly  civilized  peoples  from  small-pox  is  due  in  part  to 
greater  cleanliness  and  the  improvement  in  sanitary  condi- 
tions in  general,  which  has  been  so  marked  a  feature  of  the 
past  century.  Resting  chiefly  upon  this  thesis,  a  consider- 
able number  of  persons,  known  as  anti-vaccinationists,  deny 
altogether  the  efficiency  of  vaccination,  and  by  dwelling 
upon  the  dangers  of  impure  vaccine,  and  the  possibility  of 


320    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

introducing  the  germs  of  other  diseases  into  the  organism, 
such  persons  object  in  toto  to  vaccination,  and  especially 
to  vaccination  made  compulsory  by  statute.  The  great 
majority  of  careful  students  and  dispassionate  observers, 
however,  while  allowing  a  certain  weight  to  these  objec- 
tions, nevertheless  firmly  believe  that  the  comparative 
scarcity  of  small-pox  at  the  present  time  in  vaccinated 
peoples,  though  probably  due  in  part  to  improved  sanitary 
conditions,  is  chiefly  due  to  the  almost  universal  practice 
of  vaccination. 

In  a  disease  so  infectious,  and  even  contagious,  as  small- 
pox is,  it  may  even  be  doubted  whether  the  extraordinary 
development  of  the  possibilities  of  the  spread  of  disease 
by  travel  and  the  like  would  not  actually  have  caused  an 
increase  of  small-pox,  in  spite  of  the  general  improvement 
in  sanitary  conditions,  had  it  not  been  for  the  art  of 
vaccination.  There  is  reason,  for  example,  to  believe  that 
typhoid  fever  has  actually  increased  in  many  communities, 
owing  to  its  more  ready  dissemination,  in  spite  of  the 
diminution  which  it  must  have  undergone  under  general 
sanitary  improvements.  Typhus  fever,  on  the  other  hand, 
has  well-nigh  disappeared,  and  disbelievers  in  the  impor- 
tance and  efficiency  of  vaccination  claim  to  find  in  the 
history  of  this  disease  support  for  their  views. 

§  6.  — Nineteenth  Century  Progress  in  the  Art  of  Inocula- 
tion and   Vaccination 

The  applications  of  pure  science  usually  follow  close 
upon  the  heels  of  discovery,  and  long  before  the  full  estab- 
lishment of  bacteriology  steps  had  been  taken  to  modify 
and  control  the  action  of  bacteria  in  infectious  disease. 

As  early  as  1880  Pasteur,  reflecting  upon  the  monumen- 
tal discoveries  of  Jenner,  and  upon  the  fact  that  small-pox 
must  be  supposed  to  be  an  infectious  disease,  perceived 
that  a  reasonable  theory  of  vaccination,  provided  the  germ 


PREVENTION  OF  ANTHRAX  BY  INOCULATION  321 

theory  of  disease  were  true,  may  be  that  somehow  the 
germ  of  small-pox  has  been  modified  in  the  cow  and  ren- 
dered weak  or  "  attenuated,"  so  that  when  it  is  introduced 
into  the  human  body  it  is  no  longer  able  to  exhibit  its 
former  virulence.  Filled  with  this  idea,  he  accordingly 
undertook  to  produce  a  corresponding  weakening  or  "  atten- 
uation "  in  the  germs  of  certain  common  diseases  such  as 
chicken  cholera  and  anthrax.  In  this  attempt,  in  1880,  he 
met  with  surprising  success ;  and  it  will  be  well  worth 
while  to  note  at  this  point  an  account  of  a  public  test  of 
his  work  upon  splenic  fever  vaccination  which  has  been 
vividly  portrayed  by  his  son-in-law,  M.  Radot.1 

§  7.  — A  Public  Demonstration  by  Pasteur  of  the  Possi- 
bility of  Protective  Inoculation  of  Certain  of  the  Lower 
Animals  Against  Anthrax  or  Splenic  Fever 

"It  was  on  February  28,  1881,  that  Pasteur  communi- 
cated to  the  Academy  of  Sciences,  in  his  own  name 
and  in  those  of  his  two  fellow-workers,  the  exposition  of 
his  great  discovery.  Loud  applause  burst  forth  with 
patriotic  joy  and  pride.  And  yet  so  marvellous  were 
the  results  that  some  colleagues  could  not  help  saying, 
'There  is  a  little  romance  in  all  this.'  All  this  reminds 
one,  in  fact,  of  what  the  alchemist  of  Lesage  did  to  the 
demons  which  annoyed  him.  He  shut  them  up  in  little 
bottles,  well  corked,  and  so  kept  them  imprisoned  and  inof- 
fensive. Pasteur  shut  up  in  glass  bulbs  a  whole  world  of 
microbes,  with  all  sorts  of  varieties  which  he  cultivated  at 
will.  Virulences,  attenuated  or  terrible,  diseases,  benign 
or  deadly,  he  could  offer  all. 

"  Hardly  had  the  journals  published  the  compte  rendu 
of  his  communication,  when  the  President  of  the  Society  of 
Agriculture  in  Melun,  M.  le  Baron  de  la  Rochette,  came, 

1  "  Louis  Pasteur :  His  Life  and  Labors."     By  his  Son-in-T^aw.     From  the 
French,  by  Lady  Claud  Hamilton.     New  York  (Appleton),  1885. 
y 


322    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

in  the  name  of  the  society,  to  invite  Pasteur  to  make  a 
public  experiment  of  splenic  fever  vaccination. 

"  Pasteur  accepted.  On  April  28  a  sort  of  convention 
was  entered  into  between  him  and  the  society.  The  soci- 
ety agreed  to  place  at  the  disposal  of  Pasteur  and  his 
two  young  assistants,  Chamberland  and  Roux,  sixty  sheep. 
Ten  of  these  sheep  were  not  to  receive  any  treatment; 
twenty-five  were  to  be  subjected  to  two  vaccinal  inocula- 
tions at  intervals  of  from  twelve  to  fifteen  days,  by  two 
vaccines  of  unequal  strength.  Some  days  later  these 
twenty-five  sheep,  as  well  as  the  twenty-five  remaining 
ones,  were  to  be  inoculated  with  the  virus  of  virulent 
splenic  fever.  A  similar  experiment  was  to  be  made  upon 
ten  cows.  Six  were  to  be  vaccinated,  four  not  vaccinated  ; 
and  the  ten  cows  were  afterward,  on  the  same  day  as  the 
fifty  sheep,  to  receive  inoculation  from  a  very  virulent  virus. 

"  Pasteur  affirmed  that  the  twenty-five  sheep  which  had 
not  been  vaccinated  would  perish,  while  the  twenty-five 
vaccinated  ones  would  resist  the  very  virulent  virus ;  that 
the  six  vaccinated  cows  would  not  take  the  disease,  while 
the  four  which  had  not  been  vaccinated,  even  if  they  did 
not  die,  would  at  least  be  extremely  ill.  .  .  . 

"The  experiments  began  on  May  5,  1881,  at  four  kilo- 
metres' distance  from  Melun,  in  a  farm  of  the  commune  of 
Pouilly-le-Fort,  belonging  to  a  veterinary  doctor,  M.  Ros- 
signol,  Secretary-general  of  the  Society  of  Melun.  At 
the  desire  of  the  Society  of  Agriculture,  a  goat  had  been 
substituted  for  one  of  the  twenty-five  sheep  of  the  first  lot. 
On  the  5th  of  May  they  inoculated,  by  means  of  the  little 
syringe  of  Pravaz,  —  that  which  is  used  in  all  hypodermic 
injections,  — twenty-four  sheep,  the  goat  and  six  cows  with 
five  drops  of  an  attenuated  splenic  virus.  .  . 

"  On  May  3 1  very  virulent  inoculation  was  effected. 
Veterinary  doctors,  inquisitive  people  and  agriculturists 
formed  a  crowd  round  this  little  flock.  The  thirty-one 
vaccinated  subjects  awaiting  the  terrible  trial  stood  side  by 


A  DEMONSTRATION  OF  ANTHRAX   VACCINATION    323 

side  with  the  twenty-five  sheep  and  the  four  cows,  which 
awaited  also  their  first  turn  of  virulent  inoculation.  Upon 
the  proposal  of  a  veterinary  doctor,  who  disguised  his 
scepticism  under  the  expressed  desire  to  render  the  trials 
more  comparative,  they  inoculated  alternately  a  vaccinated 
and  a  non-vaccinated  animal.  A  meeting  was  then  arranged 
by  Pasteur  and  all  other  persons  present  for  Thursday, 
June  2,  thus  allowing  an  interval  of  forty-eight  hours  after 
the  virulent  inoculation. 

"  More  than  two  hundred  persons  met  that  day  at  Melun. 
The  Prefect  of  Seine-et-Marne,  M.  Patinot,  senators,  gen- 
eral counsellors,  journalists,  a  great  number  of  doctors,  of 
veterinary  surgeons  and  farmers ;  those  who  believed,  and 
those  who  doubted,  came,  impatient  for  the  result  On 
their  arrival  at  the  farm  of  Pouilly-le-Fort,  they  could  not 
repress  a  shout  of  admiration.  Out  of  the  twenty-five 
sheep  which  had  not  been  vaccinated,  twenty-one  were 
dead ;  the  goat  was  also  dead ;  two  other  sheep  were 
dying,  and  the  last,  already  smitten,  was  certain  to  die 
that  very  evening.  The  non-vaccinated  cows  had  all 
voluminous  swellings  at  the  point  of  inoculation,  behind 
the  shoulder.  The  fever  was  intense,  and  they  had  no 
longer  strength  to  eat.  The  vaccinated  sheep  were  in  full 
health  and  gayety.  The  vaccinated  cows  showed  no  tumor ; 
they  had  not  even  suffered  an  elevation  of  temperature, 
and  they  continued  to  eat  quietly. 

"  There  was  a  burst  of  enthusiasm  at  these  truly  marvel- 
lous results.  The  veterinary  surgeons  especially,  who  had 
received  with  entire  incredulity  the  anticipations  recorded 
in  the  programme  of  the  experiments,  who  in  their  conver- 
sations and  in  their  journals  had  declared  very  loudly  that 
it  was  difficult  to  believe  in  the  possibility  of  preparing  a 
vaccine  capable  of  triumphing  over  such  deadly  diseases  as 
fowl  cholera  and  splenic  fever,  could  not  recover  from  their 
surprise.  They  examined  the  dead,  they  felt  the  living.  .  .  . 

"  Having  suddenly  become  fervent  apostles  of  the  new 


324    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

doctrine,  the  veterinary  surgeons  went  about  proclairhing 
everywhere  what  they  had  seen.  One  of  those  who  had 
been  the  most  sceptical  carried  his  proselytizing  zeal  to 
such  a  point  that  he  wished  to  inoculate  himself.  He  did 
so  with  the  two  first  vaccines,  without  other  accident  than 
a  slight  fever.  It  required  all  the  efforts  of  his  family  to 
prevent  him  from  inoculating  himself  with  the  most  virulent 
virus. 

"  An  extraordinary  movement  was  everywhere  produced 
in  favor  of  vaccination.  A  great  number  of  agricultural 
societies  wished  to  repeat  the  celebrated  experiment  of 
Pouilly-le-Fort.  The  breeders  of  cattle  overwhelmed  Pas- 
teur with  applications  for  vaccine.  Pasteur  was  obliged  to 
start  a  small  manufactory  for  the  preparation  of  these  vac- 
cines, in  the  Rue  Vauquelin,  a  few  paces  from  his  labora- 
tory. At  the  end  of  the  year  1881  he  had  already  vac- 
cinated 33,946  animals.  This  number  was  composed  of 
33»55°  sheep,  1254  oxen,  142  horses.  In  1882  the  number 
of  animals  vaccinated  amounted  to  399,102,  which  included 
47,000  oxen  and  2000  horses.  In  1883,  100,000  animals 
were  added  to  the  total  of  1882." 

These  experiments  drew  universal  attention  to  the  sub- 
jects of  immunity  and  susceptibility.  It  had  been  long 
recognized  that  there  is  such  a  thing  as  natural  immunity  as 
well  as  natural  susceptibility,  and  the  case  of  small-pox  is 
familiar  testimony  to  the  fact  that  there  is  such  a  thing  as 
acquired  immunity.  Pasteur's  experiments,  moreover,  had 
abundantly  demonstrated  that  immunity  to  anthrax  could 
be  artificially  produced.  These  ideas  fell  in  well  with  those 
concerning  the  toxins  referred  to  in  the  third  chapter 
(PP-  57.  59)-  for  it  was  possible  to  see  how,  either  by  reducing 
the  virulence  of  the  toxins,  or  by  accustoming  the  organism 
to  them,  gradually  insusceptibility  or  virtual  immunity  might 
be  produced. 

To  discuss  all  aspects  of  this  question,  interesting  though 
it  would  be,  would  carry  us  too  far  into  the  domain  of  bac- 


ANTITOXINS   AS   PROPHYLACTICS  325 

teriology  and  medicine.  Suffice  it  to  say  that  in  one  in- 
stance, at  least,  the  studies  upon  this  subject  have  already 
borne  the  richest  fruit.  Thanks  to  Behring,  Roux  and 
others,  we  are  now  able  to  produce  at  will  not  only  the 
toxin  of  diphtheria,  but  also  by  simple  procedures  the  an- 
tidote to  this  poison  which  is  appropriately  called  its  "  anti- 
toxin." (Cf.  p.  83.) 

§  8. — Insusceptibility  produced  by  Inoculation  of  Anti- 
toxins,    Serum  Therapy 

A  logical  extension  of  the  arts  of  inoculation  and  vacci- 
nation now  consists  in  the  use  of  antitoxins  to  reenforce 
the  natural  insusceptibility  of  the  organism,  whether  partial 
or  complete.  If,  for  example,  as  we  have  reason  to  believe, 
the  specific  diseases  known  as  small-pox,  plague,  diphtheria, 
etc.,  are  aroused  by  specific  chemical  excitants  or  poisons 
of  the  physiological  mechanism,  themselves  produced  by 
specific  living  excitants  known  as  micro-organisms,  it  is 
reasonable  to  suppose. that  those  animals  or  persons  which 
are  immune  to  these  diseases  must  possess  some  special 
antidote  capable  of  destroying  the  effects  of  the  specific 
poisons  or  toxins  which  they  generate  and  which  are 
characteristic  of  them.  By  inductive  reasoning  of  this 
sort  Behring  and  Roux  undertook  to  settle  the  question 
by  gradually  producing  immunity  to  the  toxin  of  diph- 
theria in  horses,  and  then  using  the  antitoxins  presumably 
present  in  the  blood  of  the  immune  horses  as  a  curative  or 
preventive  weapon  against  diphtheria  in  man.  We  have 
already  dwelt  upon  this  subject  in  the  preceding  para- 
graph and  elsewhere,  and  need  not  touch  upon  it  further 
here.  Suffice  it  to  say,  that  it  is  now  generally  admitted 
on  all  sides  that  the  antitoxin  of  diphtheria  may  be  em- 
ployed successfully  not  only  to  reenforce  the  organism 
already  suffering  from  the  disease,  but  also  as  a  prophy- 
lactic or  means  of  prevention  in  others  susceptible  but 
not  yet  affected.  The  chain  of  reasoning  and  the  experi- 


326    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

mental  work  involved  in  this  discovery  constitute  one  of 
the  most  beautiful  examples  of  patient  scientific  work  in 
the  whole  history  of  experimental  medicine  and  sanitary 
science. 

§  9.  —  Antisepsis  and  the  Prevention  of  Infection  by 
Antiseptics 

Theoretically,  it  should  be  possible  to  inhibit  or  check 
the  progress  of  any  infectious  disease  within  the  organism 
by  the  use  of  substances  capable  of  interfering  with  or 
inhibiting  the  growth  and  multiplication  of  the  micro- 
organisms involved.  In  practice,  however,  to  do  this  is 
far  more  difficult  than  might  be  expected,  so  that  the  pre- 
vention of  infection  by  exclusion  (asepsis},  the  prevention 
of  infection  by  insusceptibility  (immunity,  natural  or  ac- 
quired), and  external  disinfection,  or  the  destruction  and 
removal  of  infection  from  the  environment,  —  which  lat- 
ter subject  will  be  dealt  with  in  the  next  chapter,  —  are 
infinitely  more  valuable  methods  of.  procedure  in  sanitary 
science.  The  reason  for  this  is  to  be  found  partly  in  the 
difficulty  of  bringing  to  bear  upon  micro-organisms,  scat- 
tered throughout  masses  of  tissue  or  widely  distributed  in 
ducts  or  canals,  agents  capable  of  inhibiting  or  checking 
their  activity,  but  chiefly  in  the  fact  that  such  agents  are 
almost  of  necessity  harmful  to  the  organism  which  it  is 
desired  to  benefit ;  for  it  is  a  fact  which  should  never  be 
forgotten  that  micro-organisms  capable  of  producing  infec- 
tious disease,  although  removed  from  man  and  the  higher 
animals  by  the  whole  length  of  the  animal  and  vegetable 
kingdoms,  are,  nevertheless,  composed  of  protoplasm,  very 
similar  in  its  chemical  and  physical  properties  to  that  which 
constitutes  the  basis  of  the  higher  forms  ;  so  that,  broadly 
speaking,  and  doubtless  with  many  exceptions,  we  ought 
to  expect  a  sensitiveness  to  inhibiting  agents  in  the  one 
class  of  organisms  similar  to  that  in  the  other. 

Agents  capable  of  checking  or  inhibiting  the  growth  of 


ANTISEPTICS    VS.    DISINFECTANTS  327 

micro-organisms,  in  the  .way  above  suggested,  but  without 
necessarily  killing  them,  are  known  as  "antiseptics,"  and 
the  process  of  such  inhibition  or  checking  as  "  antisepsis." 
Obviously,  all  disinfectants  or  destroyers  of  infection  are 
also  antiseptics ;  but  the  reverse  is  not  true,  for  antiseptics 
are  not  necessarily  disinfectants.  When  sanitary  surgery 
was  first  proposed,  it  was  generally  described  as  antiseptic 
surgery,  and  it  was  held,  at  least  by  some,  that  its  object 
was  to  inhibit  the  activity  of  organisms  already  introduced 
into  the  organism  through  wounds.  Very  soon,  however, 
it  became  clear  that  the  process  was  most  successful  when 
made  aseptic  rather  than  antiseptic ;  and  while  to-day  the 
washings  and  dressings  employed  in  surgery  may,  and 
probably  sometimes  do,  act  as  antiseptics,  the  almost  uni- 
versal endeavor  is  to  secure  asepsis,  and  not  to  run  the 
risk  of  possibly  imperfect  antisepsis.  We  may  safely 
grant,  nevertheless,  the  possibility  that  the  organism  itself 
has  antiseptic  as  well  as  disinfecting  powers. 

§  10. — Intestinal  Antisepsis 

It  has  been  proposed  to  introduce  into  the  alimentary 
canal  in  certain  diseases  agents  which,  while  capable  of 
checking  the  progress  or  multiplication  of  the  organisms 
of  infectious  disease  there  present,  shall  at  the  same  time 
be  harmless  to  the  tissues  lining  the  canal.  This  procedure 
is  properly  described  as  intestinal  antisepsis ;  but,  while 
well  worthy  of  investigation,  must  always  be  subject  to  the 
drawback  of  constant  danger  of  damage  to  the  living  walls 
by  any  agents  powerful  enough  to  affect  the  perhaps  far 
more  hardy  micro-organisms  of  disease. 

§  n. —  The  Control  of  Infection  in  Decomposition  and 

Decay 

From  the  sanitary  point  of  view,  decomposition  and 
decay  must  always  and  everywhere  be  regarded  with  sus- 


328    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

picion,  although  they  are  normal  processes  in  nature  and 
often  of  high  usefulness  in  the  arts  and  industries  of 
daily  life.  The  reason  for  this  is  that  they  are  usually 
effected  by  bacteria  or  other  micro-organisms  with  which 
those  of  infections  may,  in  theory  at  least,  be  readily  asso- 
ciated. Moreover,  the  chemical  products  of  decomposition 
and  decay  are  sometimes  objectionable  or  even  dangerous, 
so  that  the  race  in  its  long  experience  has  properly  enough 
come  to  regard  them  with  suspicion.  Their  prevention  is 
obviously,  therefore,  often  desirable,  especially  in  the  case 
of  food  products,  and  for  this  purpose  antiseptics  such  as 
cold,  dryness,  weak  acids,  condensing  and  partial  steriliza- 
tion are  often  practically  useful. 

§  12.  —  Sanitary  Aspects  of  Refrigeration  and  Cold  Storage 

Probably  the  best  of  all  antiseptics  is  simple  cold,  and 
this  is  now  applied  to  the  prevention  of  decomposition  and 
decay  of  food  almost  universally.  Before  the  introduction 
of  the  use  of  ice,  low  temperatures  were  sought  by  house- 
wives by  the  keeping  of  foods  in  cold  cellars,  deep  wells 
and  the  like ;  but  within  the  past  fifty  years  the  use  of 
ice,  at  least  in  America,  has  become  a  commonplace. 
The  household  refrigerator  is  a  simple  antiseptic  device 
for  postponing  the  decomposition  and  decay  of  meats, 
milk,  vegetables,  fruit  and  the  like.  More  elaborate  re- 
frigerators, furnishing  antisepsis  in  similar  fashion,  are 
provided  in  markets,  groceries,  milk-houses  and  like  es- 
tablishments ;  while  in  nearly  all  large  cities  there  are 
nowadays  huge  structures  known  as  "cold-storage"  ware- 
houses, in  which  vast  quantities  of  perishable  materials 
are  successfully  subjected  to  the  antiseptic  action  of  cold. 
The  equipment  of  the  best  types  of  cold-storage  ware- 
houses is  elaborate  and  costly,  for  they  must  be  sub- 
stantially and  carefully  built,  furnished  with  efficient 
ammonia  machines,  or  similar  appliances  for  the  produc- 


REFRIGERATION   AND  ANTISEPSIS  329 

tion  of  cold,  and  capable  of  dry  ventilation  to  prevent 
excessive  moisture.  Cold  for  antiseptic  purposes  and 
the  preservation  of  food  materials  is  also  distributed,  at 
least  in  Boston,  through  pipes  to  various  markets,  which 
maintain  rooms  chilled  to  a  low  temperature  very  much  as 
steam  is  circulated  in  winter  for  the  heating  of  apartments. 
The  sanitary  value  of  systems  of  this  sort  is  probably  great, 
for  there  is  reason  to  believe,  as  has  been  pointed  out  in  a 
previous  chapter  (p.  259),  that  the  germs  of  infectious  dis- 
ease do  not  as  a  rule  long  survive  at  very  low  temperatures. 

§  13.  —  Sanitary  Aspects  of  Desiccation,  Drying, 
Evaporation 

A  favorite  and  primitive  method  of  food-preserving  for 
meats,  fruits  and  various  other  food  materials  has  long 
been  in  use  under  the  name  of  "  drying,"  and  that  this 
method  possesses  important  sanitary  advantages  seems 
highly  probable,  inasmuch  as  the  micro-organisms  of  dis- 
ease do  not  readily  withstand  prolonged  desiccation.  If, 
for  example,  fruits,  meats  or  vegetables  which  it  is  pro- 
posed to  use  for  food  happen  to  be  in  any  way  infected, 
but  are  afterwards  thorongJily  dried,  there  is  reason  to 
believe  that  such  desiccation  is  highly  unfavorable  to  the 
disease  germs  present.  Their  spores,  however,  in  some 
cases  probably  survive,  and  it  is  possible  that  some  of  the 
vegetative  germs  even  may  not  perish ;  but  yet  the  process 
of  desiccation  plainly  possesses  valuable  sanitary  advan- 
tages. These  are  perhaps  less  important  than  would  other- 
wise be  the  case  were  it  not  for  the  fact  that  dried  foods  are 
rarely  eaten  without  having  been  first  not  only  moistened 
but  also  thoroughly  cooked  or  heated,  so  that  the  danger 
of  the  dissemination  of  disease  by  dried  foods  such  as 
dried  beef,  dried  apricots,  dried  beans,  etc.,  is  probably 
small. 


330    THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

§  14.  —  Sanitary  Aspects  of  Smoking 

A  similar  line  of  reasoning  applies  to  the  use  of  smoked 
foods,  such  as  fish,  beef  or  hams.  In  this  case  the  pro- 
cess of  drying  is  accompanied  by  smoking,  so  that  what- 
ever antiseptic  or  disinfecting  effects  may  reside  in  smoke 
are  added  to  those  of  desiccation.  Smoked  and  dried 
herring,  for  example,  are  in  many  cases  hung  in  vast 
quantities  in  comparatively  close  buildings,  and  subjected 
for  a  considerable  period  to  the  warmth  and  smoke  of  a 
slow  fire;  and  inasmuch  as  there  is  reason  to  believe  that 
smoke  possesses  important  disinfecting  properties  due  to 
the  creosote  or  other  materials  which  it  contains,  the  pro- 
cess must  be  regarded  as  one  of  considerable  sanitary 
significance. 

Furthermore,  inasmuch  as  smoked  foods  are  not  in- 
frequently eaten  without  cookery  of  any  kind,  their 
treatment  is  of  special  interest  to  the  sanitarian.  In  all 
probability,  the  processes  to  which  smoked  foods  have 
been  subjected,  while  not  such  as  to  produce  complete 
disinfection,  are  nevertheless  sufficient  to  destroy  most  of 
the  germs  of  infectious  disease.  If,  nevertheless,  after 
having  been  smoked  and  dried,  such  foods  are  handled 
by  unclean  persons  and  then  eaten  raw,  they  constitute 
a  source  of  danger  similar  to  that  which  resides  in  all 
raw  foods. 

§  1 5«  —  Of  Preserving 

The  process  known  as  preserving  is  one  in  which  decom- 
position is  arrested  or  prevented  by  the  use  of  syrups  or 
other  substances  of  considerable  density,  which  in  one 
way  or  another  furnish  an  unfavorable  environment  to  the 
organisms  of  decomposition  and  decay.  A  similar  state- 
ment may  probably  be  made  in  this  case  as  in  the  pre- 
ceding, namely,  that  if  the  food  to  be  preserved  be  infected, 
most  of  the  infectious  organisms  will  probably  be  destroyed 


ANTISEPTIC  PROCESSES   IN   THE   HOUSEHOLD    331 

in  the  process,  though  some  may  survive  ;  and  if  later  the 
food  material  of  which  they  constitute  a  part  be  eaten 
without  having  been  cooked,  a  certain  amount  of  danger 
may  ensue.  The  dangers  in  this  case,  also,  are,  however, 
probably  small. 

§  1 6.  —  Of  Canning 

The  art  of  canning  when  properly  carried  out  consists  hi 
a  total  destruction  of  all  micro-organisms  present,  or  dis- 
infection, and  this  process  therefore  belongs  properly  in  the 
following  chapter.  It  sometimes  happens,  nevertheless, 
that  canned  foods  are  only  imperfectly  sterilized,  and  when 
this  is  the  case,  it  is  clear  that  such  foods  may  be  bearers 
not  only  of  fermentation,  decomposition  and  decay,  but,  in 
special  instances,  of  infection  as  well.  At  the  same  time, 
inasmuch  as  it  is  likely  that  the  germs  of  putrefaction  and 
decay  will  have  made  the  contents  of  such  cans  unattrac- 
tive or  repulsive,  there  is  probably  very  slight  danger  of 
infection  from  canned  foods.  In  some  cases,  indeed, 
this  may  not  be  true,  the  germs  remaining  after  partial 
sterilization  being  of  a  kind  incapable  of  producing 
ordinary  and  obvious  decomposition  and  decay.  For 
example,  sweet  corn  after  imperfect  sterilization  in  cans 
not  infrequently  sours  more  or  less,  owing  to  the  presence 
of  certain  bacteria  capable  of  producing  lactic  acid  from 
the  substances  present,  and  in  this  case  the  souring  may 
not  have  proceeded  so  far  as  to  make  the  corn  inedible. 
Under  these  circumstances,  the  possibility  of  the  convey- 
ance of  infectious  materials  must  be  allowed ;  but,  as  has 
been  stated,  its  likelihood  is  probably  only  slight. 

§  !7.  —  Of  Pickling 

Another  important  method  of  securing  disinfection  and 
antisepsis  is  the  art  of  pickling,  or  the  preservation  of 
foods  in  brines,  vinegar,  weak  acids  and  the  like.  In  this 


332     THE  PREVENTION  AND  INHIBITION  OF  INFECTION 

case,  while  the  antiseptics  employed  are  sufficient  to  pre- 
vent decomposition  and  decay,  it  is  unlikely  that  thorough 
sterilization  or  disinfection  is  always  brought  about,  and 
the  bare  possibility  of  the  distribution  of  disease  through 
infected  foods  thus  preserved  must  be  kept  in  mind,  al- 
though it  is  not  probable  that  much  disease,  other  than  a 
few  "  sporadic  "  cases,  actually  is  caused  in  this  way. 

§  1 8.  —  Sanitary  Aspects  of  Pasteurising 

A  process  now  much  used  for  food-preserving  is  that 
form  of  partial  sterilization  by  heat  known  as  pasteurizing. 
This  is  now  much  employed  in  the  dairy  industry  in  the 
pasteurizing  of  milk  and  of  cream.  It  is  of  immense  im- 
portance as  a  practical  means  of  food-preserving,  and  from 
the  standpoint  of  sanitary  science,  if  carefully  conducted, 
is  also  of  great  value.  As  carried  out,  for  example,  in  the 
preservation  of  milk,  the  attempt  is  made  to  use  a  tempera- 
ture high  enough  to  secure  the  destruction  of  disease-pro- 
'ducing  germs,  yet  not  so  high  as  to  produce  the  well-known 
"  cooked  "  taste.  There  is  much  evidence  of  the  sanitary 
efficiency  of  this  process,  which  is  always  to  be  highly 
commended  in  the  milk  supply  industry,  but  it  cannot  be 
denied  that  unless  the  pasteurizing  is  carried  on  at  a  high 
enough  temperature  to  destroy  all  disease  germs,  such  milk 
may  still  be  the  vehicle  of  infectious  disease.  (Cf.  p.  287.) 

§  19.  —  Of  Condensing 

Condensed  foods,  such  as  condensed  milk,  are  usually 
thickened  by  heat,  but  the  temperature  employed  is  often 
insufficient  to  secure  in  itself  the  complete  destruction  of 
all  micro-organisms.  The  change  in  the  physical  condition 
involved  in  the  thickening  is  of  sanitary  value,  and  the 
whole  process  is  one  of  considerable  sanitary  importance. 
It  is  doubtful,  however,  whether,  under  certain  circum- 
stances, all  germs  of  disease  are  destroyed  in  "  condens- 


ANTISEPTICS   IN   THE   ARTS   AND   INDUSTRIES     333 

ing,"  and  the  possibility  that  condensed  foods  may  serve 
as  vehicles  of  disease  should  be  borne  in  mind,  although  it 
must  be  admitted  that  these  are  most  likely,  as  a  rule, 
safe  and  wholesome  in  this  particular. 

It  has  recently  been  proposed  to  condense  milk  and  other 
food  materials  by  cold  instead  of  by  heat.  The  purification 
of  water  by  freezing  has  already  been  dwelt  upon  in  a 
previous  chapter  (p.  252),  and  the  effect  of  cold  upon 
disease  germs  is  undoubtedly,  as  a  rule,  highly  prejudicial 
to  them,  so  that  this  process,  if  it  becomes  practical,  must 
be  allowed  to  possess  important  sanitary  advantages.  At 
the  same  time  the  possibility  of  the  survival  of  a  small  per- 
centage of  disease  germs  cannot,  in  the  present  state  of  our 
knowledge,  be  disregarded. 


CHAPTER  XIV 

ON  THE   DESTRUCTION   OR  REMOVAL   OF   INFECTION. 
DISINFECTION   AND    DISINFECTANTS 

§  i. — Definitions 

DISINFECTION  is  the  term  applied  to  any  process  by 
which  the  infectious  properties  of  anything  are  removed 
or  destroyed,  and  a  disinfectant  is  any  agent  or  factor  by 
which  this  process  may  be  brought  about.  Obviously,  dis- 
infection may  be  either  partial  or  complete,  but  the  term 
is  usually  applied  only  when  the  process,  whatever  it  may 
be,  is  completely  effective.  Disinfection  differs  from  asep- 
sis in  the  fact  that  the  presence  of  infection  in  the  material 
to  be  disinfected  is  assumed,  while  in  asepsis  the  endeavor 
is  made  to  prevent  or  forestall  infection.  In  other  words, 
disinfection  is  in  the  nature  of  cure  or  correction  of  an 
infectious  condition,  while  asepsis  is  an  effort  directed  to 
the  avoidance,  and  antisepsis  to  the  inhibition  or  control, 
of  infection.  A  little  consideration  will  show  that  all  dis- 
infectants are  naturally  antiseptics,  while  antiseptics  may 
or  may  not  be  disinfectants.  Similarly,  it  may  in  any 
particular  case  happen  that  a  disinfectant  when  diluted,  or 
allowed  to  work  for  a  brief  period  only,  may  act  as  an 
antiseptic  ;  while  an  antiseptic,  working  for  a  long  time  or 
in  unusual  concentration,  may  become  a  disinfectant.  As 
has  been  pointed  out  in  the  previous  chapter,  antisepsis  is 
of  value  largely  in  food-preserving,  to  which  process  disin- 
fection may  also  be  applied.  On  the  other  hand,  disinfec- 
tion may  often  be  too  poisonous  or  drastic  for  application 
to  food-preserving,  and  in  general  the  term  is  usually 
applied  to  the  purification  of  substances  (clothing,  houses, 

334 


DISINFECTANTS    VS.  ANTISEPTICS  335 

etc.)  other  than  food  from  the  germs  of  disease,  and  only 
rarely  to  the  arts  of  food-preserving. 


§  2.  —  Disinfection  by  Chemical  Agencies 

Fire  is  from  every  point  of  view  the  most  valuable  and 
effective  disinfectant.  We  have  already  pointed  out  in  a 
previous  chapter  how  the  disinfection  of  food  by  cookery 
is  perhaps  the  most  valuable  part  of  that  process,  and  the 
experience  of  the  race  has  taught  that  it  is  no  less  effec- 
tive in  other  directions.  Infected  houses,  infected  bedding, 
infected  clothing,  are  readily  disinfected  by  fire.  Fire  has 
always  been,  and  probably  will  always  continue  to  be,  the 
simplest,  the  readiest,  and  the  most  effective  of  all  disin- 
fectants. It  has  often  been  suggested  that  the  great  fire 
of  London  in  1666,  following  as  it  did  hard  after  the 
plague,  was  probably  a  most  important  factor  in  the 
purification  of  the  city  and  the  control  of  that  dread 
disease. 

The  precise  manner  in  which  fire  destroys  infection  is 
easy  to  understand.  By  the  production  of  a  temperature 
so  high  that  no  life  can  withstand  it,  and  the  destruction 
of  organic  matter,  the  germs  of  disease,  whether  animal  or 
vegetable,  are  readily  destroyed,  and  fire  may  perhaps  be 
considered,  by  virtue  of  the  chemical  decomposition  which 
it  brings  about,  as  essentially  a  chemical  disinfectant. 

Next  in  readiness  and  efficiency  after  fire  come  the 
chemical  poisons,  such  as  corrosive  sublimate  (mercuric 
chloride),  carbolic  acid,  strong  mineral  acids  and  alkalies, 
sulphurous  acid,  formic  aldehyde  and  the  like.  These, 
by  producing  chemical  decompositions  upon  or  within  the 
cells  of  the  organized  infectious  elements,  so  alter  the 
chemical  composition  of  the  latter  as  to  destroy  their  vital 
activity.  In  some  cases,  owing  to  special  protective  condi- 
tions, or  forms  which  the  infectious  elements  assume,  all  of 
these  poisons  may  become  for  a  longer  or  shorter  time  more 


336  DISINFECTION 

or  less  ineffective  —  a  state  of  affairs  which  is  probably 
common  under  the  action  of  various  so-called  disinfectants. 


§  3.  —  Disinfection  by  Physical  Agencies 

Closely  analogous  to  the  effects  just  described  as  due  to 
fire  and  poisons  are  those  which  come  from  heat,  a  mod- 
erate degree  of  temperature  being  favorable  to  the  con- 
tinued life  of  organized  infectious  elements,  but  higher 
temperatures  being  more  and  more  prejudicial  to  them. 
In  general,  it  may  be  stated  that  the  boiling  temperature 
of  water  destroys  most  ordinary  infectious  materials,  doubt- 
less by  causing  chemical  changes  similar  to  those  referred 
to  in  the  previous  section ;  but,  as  has  been  shown  in  the 
previous  chapter,  it  is  often  necessary  to  use  a  tempera- 
ture considerably  higher  in  order  to  sterilize,  for  example, 
canned  .  foods.  Moreover,  microbes  have  been  found 
which,  though  probably  not  capable  of  producing  disease, 
are  nevertheless  able  to  withstand  continuous  boiling  for 
eight  hours  or  more.  The  assumption  in  this  case  is  that 
spores  are  present,  and  are  specially  resistant  in  regard 
to  conductivity  of  heat,  so  that  their  interior  does  not, 
until  after  a  very  long  time,  rise  in  temperature  to  the 
death  point.  It  is  not  certain,  however,  whether  their 
resistance  is  due  to  the  fact  that  they  are  good  non-conduc- 
tors or  to  some  special  property  which  is  not  understood. 

Cold  in  general  is  less  effective  than  heat  as  a  disin- 
fectant, and  perhaps  scarcely  has  a  place  among  disinfec- 
tants. Nevertheless  the  evidence  referred  to  in  the  case 
of  the  purification  of  ice  in  freezing  (p.  261)  indicates  that 
cold  does  in  fact  play  a  very  considerable  part,  not  only  as 
an  antiseptic,  but  also  as  a  disinfectant.  The  experience 
of  the  race,  moreover,  points  in  the  same  direction.  In 
the  southern  United  States  cold  weather  is  rightly  believed 
to  diminish  materially  the  dangers  from  yellow  fever  and 
similar  diseases,  and  there  is  reason  to  believe  that  the 


BY   HEAT,   COLD,  DRYNESS,  LIGHT  337 

infectious  elements  of  this  disease,  as  well  as  of  Asiatic 
cholera,  typhoid  fever,  and  probably  many  other  diseases, 
are  largely  destroyed  by  prolonged  exposure  to  even  a 
moderate  degree  of  cold,  i.e.  by  temperatures  in  the  vicinity 
of  the  freezing-point  of  water. 

Another  powerful  agent  of  disinfection  is  dryness.  Liv- 
ing things  require  not  only  a  favorable  temperature,  but 
also  considerable  moisture ;  and  a  high  degree,  or  a  long 
period,  of  dryness  undoubtedly  contributes  to  the  destruc- 
tion of  germ  life.  It  is  doubtful,  however,  whether  dry- 
ness,  as  it  occurs  in  periods  of  drought  or  in  nature 
generally,  is  a  perfect  disinfectant.  There  is  reason  to 
believe  that  precisely  as  prolonged  moderate  heat  is 
required  in  order  to  destroy  infection,  and  precisely  as 
prolonged  low  temperatures  are  necessary,  so  prolonged 
dryness  is  required  unless  it  be  brought  about  in  the  most 
thorough  manner  and  by  artificial  means,  and  possibly  not 
even  then. 

One  of  the  most  interesting  discoveries  in  bacteriology 
of  recent  years  was  that  which  showed  the  germicidal 
efficiency  of  light.  It  had  been  known  for  some  time  to 
botanists  that  insolation,  or  the  exposure  of  living  organs 
or  organisms  to  the  light,  appeared  to  bring  about  a  rela- 
tively rapid  disintegration  of  their  protoplasm.  Much 
evidence  pointing  in  this  direction  was  collected  during 
the  various  studies  which  were  made  upon  the  function 
of  chlorophyl,  one  view  in  particular  (that  of  Pringsheim) 
being  known  as  the  "  screen  "  theory,  in  which  it  was  sup- 
posed that  the  green  pigment  of  leaves  serves  as  a  screen 
to  protect  the  underlying  protoplasm  from  the  injurious 
rays  of  the  sun.  It  is  now  well  known  that  sunlight  has 
a  marked  germicidal  power,  and  is,  therefore,  an  important 
disinfectant.  It  is  probably  for  this  reason,  in  part  at  least, 
that  the  human  race  has,  by  experience,  found  sunlight  so 
desirable  in  human  dwellings  and  so  effective  an  aid  to 
healthy  living. 


338  DISINFECTION 

Much  has  been  hoped  for,  by  some,  from  electricity  as 
a  disinfectant ;  but  the  experimental  evidence  thus  far 
available  does  not  seem  to  justify  any  great  expectations 
in  this  direction.  Infectious  organisms  are  themselves  so 
similar  in  their  resistance  to  the  human  body,  or  the  foods 
in  or  upon  which  they  may  be,  that  it  does  not  at  present 
seem  likely  that  it  will  in  the  near  future  be  possible  to 
destroy  such  germs  by  electric  currents,  without,  at  the 
same  time,  destroying  their  hosts,  or  the  media  upon  which 
they  may  reside. 

§  4.  —  Disinfection  by  Mechanical  Means 

The  processes  thus  far  described  or  referred  to  for  the 
most  part  bring  about  disinfection  by  destruction  of  the 
infectious  elements.  The  definitions  given  at  the  begin- 
ning of  this  chapter,  however,  imply  the  possibility,  in 
some  cases  at  least,  of  removal  without  destruction;  and 
such  processes  are,  in  fact,  conceivable  and  practicable. 

Such  a  separation  or  removal  may,  for  example,  take 
place  mechanically  in  filtration.  If  a  drinking  water,  for 
instance,  can  be  made-  to  pass  through  a  material  of  which 
the  pores  are  so  fine  as  to  be  impassable  by  the  infectious 
elements,  while  yet  permeable  by  water,  then,  clearly,  the 
former  may  be  held  back  while  the  latter  may  pass  on. 
Such  a  mechanical  filtration  is  plainly  one  form  of  disin- 
fection. 

Another  form  of  mechanical  disinfection  is  that  effected 
by  gravity.  It  has  been  pointed  out  above  that  a  polluted 
water  brought  to  rest  and  stored  may  be  purified,  in  part, 
by  sedimentation.  If  the  infectious  elements  are  heavier 
than  the  liquid  in  which  they  float,  they  may  be  drawn 
down  by  gravity  and  deposited  upon  the  mud  at  the  bottom 
of  a  reservoir,  lake  or  other  body  of  quiet  water;  and  such 
sedimentation  may  either  constitute  or  contribute  to  a 
genuine  disinfection  of  a  water  supply. 


BY  FILTRATION,  GRAVITY,  STARVATION,  ETC.      339 

§  5 .  —  Disinfection  by  Biological  Agencies 

If  the  infectious  elements  in  any  given  case  can  be 
detained  long  enough  in  the  absence  of  food,  starvation 
must  eventually  ensue;  and  there  is  little  doubt  that  in 
certain  water  supplies,  and  elsewhere,  this  condition  con- 
stitutes, or  may  constitute,  a  genuine  factor  of  disinfection. 
Perhaps  it  is  not  too  much  to  say  that  starvation  of  the 
infectious  elements  is,  broadly  speaking,  and  next  to  fire, 
one  of  the  best  of  all  disinfectants.  In  regard  to  the  cycli- 
cal changes  to  which  infectious  elements  are  subject,  we 
have  very  little  knowledge,  but  if  old  age  may  be  con- 
ceived to  be  a  characteristic  of  the  lowest  forms  of  life, 
—  a  question  which  is  still  under  debate,  —  then  this  also 
may  well  constitute  one  of  the  agents  of  disinfection. 

Finally,  we  may  have,  acting  together  in  cooperation, 
two  or  more  of  the  agencies  already  mentioned,  such,  for 
example,  as  cold  and  dryness,  light  and  heat,  or  poisons 
and  starvation,  these  together  constituting  what  are  called 
"unfavorable  environments."  Contrary  to  the  opinion 
which  was  held  in  the  earlier  periods  of  our  acquaintance 
with  micro-organisms,  we  are  now  able  to  perceive  that 
each  of  these  must  be  carefully  adjusted  to  its  environment, 
if  it  is  to  survive  long;  and  perhaps  no  factors  are  more 
effective  in  the  control  of  infection  than  the  unfavorable 
environments  of  infinite  variety  to  which  such  elements 
must  be  subjected.  It  is  probably  here  that  we  find  the 
explanation  of  the  sanitary  improvement  observed  in  the 
storage  of  water,  ice,  etc.  (cf.  pp.  237,  249,  261). 

§  6.  —  The  Problem  of  Disposal  of  the  Dead 

The  question  of  sanitary  disposal  of  the  dead  concerns 
us  chiefly  so  far  as  relates  to  its  bearing  upon  the  spread 
of  infectious  disease,  and  it  is  only  this  aspect  of  the 
subject  which  will  be  touched  upon  here.  It  has  been 


340  DISINFECTION 

repeatedly  stated  in  earlier  chapters  that  the  bacterial 
population  of  the  living  earth  is  a  scavenging  population, 
which  removes  from  the  surface  of  the  earth  the  organic 
matters  falling  upon  it,  and  converts  them  into  inorganic 
matters.  The  same  thing  is  true  of  organic  matters  placed 
at  a  moderate  depth  in  the  crust  of  the  earth.  The  sub- 
soil is  less  abundantly  supplied  with  bacteria  than  the  loamy 
layers  of  vegetable  mould  at  or  near  the  surface,  but  yet 
contains  a  sufficient  number  of  them  to  bring  about  the 
somewhat  less  rapid  decomposition  of  organic  matters. 
Human  bodies,  therefore,  buried  in  the  earth,  and  the 
wooden  boxes  in  which  they  are  usually  interred,  are  in 
time  gradually  mineralized,  and,  in  favorable  cases,  nearly 
all  traces  of  organic  matter  disappear.  The  use  of  metal 
caskets,  embalming  fluids  (which  are  usually  powerful 
disinfectants,  or  at  least  strong  antiseptics),  simply  delay 
the  process.  If  any  infectious  germs  be  present  in  or 
about  the  dead  body,  these  are  obviously  harmless  so  long 
as  they  remain  in  the  earth.  The  only  question  is,  whether 
they  may  survive  to  be  brought  to  the  surface  by  earth- 
worms or  other  agencies;  for  if  so,  after  having  been 
pulverized,  they  may  be  distributed  by  the  wind.  This 
subject  has  been  carefully  investigated  by  various  ob- 
servers, and  there  seems  little  reason  to  believe  that 
infectious  materials  may  readily  be  spread  abroad  from 
infected  bodies  buried  in  the  earth.  Moreover,  there  are 
good  grounds  for  believing  that  owing  to  unfavorable 
environment,  old  age,  or  other  disinfecting  agencies,  the 
infectious  germs,  if  present,  will  generally  not  very  long  sur- 
vive ;  so  that  we  appear  to  be  safe  in  concluding  that  from 
the  sanitary  point  of  view  there  is  little  to  be  feared  from 
disposal  of  the  dead  by  interment. 

Much  has  been  written  and  claimed  in  regard  to  nox- 
ious vapors  arising  from  graveyards  and  in  regard  to 
graveyards,  especially  when  crowded,  as  sources  of  disease. 
These  ideas,  however,  are  not  founded  upon  good  evidence, 


THE   PROBLEM   OF  DISPOSAL   OF  THE  DEAD     341 

and  there  is  reason  to  believe  that  whatever  diseases 
may  have  appeared  in  the  neighborhood  of  graveyards, 
have  had  their  origin  elsewhere. 

§  7. —  Interment  vs.  Cremation 

If  what  has  just  been  said  is  true,  no  very  powerful  argu- 
ment can  be  found  in  sanitary  science  for  cremation  as 
opposed  to  interment.  Nevertheless,  the  author  firmly 
believes  in  cremation  as  the  better  process  for  the  disposal 
of  the  dead,  but  simply  for  the  following  reasons :  first, 
because  it  is  speedy  rather  than  tardy,  and  by  cleanly  com- 
bustion rather  than  foul  decay,  —  fire  accomplishing  in  a  few 
hours  a  decomposition  and  a  mineralization  which  require 
years  at  the  hands  of  the  bacteria ;  second,  because  of  the 
smaller  space  required  for  the  keeping  of  the  ashes  and 
the  possibility  of  restricting  the  immense  areas  likely  in  the 
future  to  be  required  for  cemeteries ;  and  third,  because  of 
the  removal  of  all  ground  for  debate  as  to  the  possibility  of 
damage  from  noxious  vapors  or  the  origin  of  disease  from 
graveyards. 

§  8.  —  Special  Disinfectants 

The  art  of  disinfection  is  a  difficult  and  delicate  one  if  it 
is  desired  that  the  disinfection  in  any  possible  case  shall  be 
absolutely  thorough  and  complete.  There  is  a  large  litera- 
ture upon  this  subject  to  which  many  references  might  be 
given ;  but  the  following  brief  statements  must  suffice  for 
a  work  devoted  to  the  principles,  rather  than  the  practice, 
of  sanitary  science. 

One  of  the  best  and  most  convenient  disinfectants,  as  has 
already  been  pointed  out,  is  fire.  Almost  every  house,  at 
least  in  temperate  latitudes,  is  provided  with  a  possible  dis- 
infecting apparatus  in  the  shape  of  a  stove,  a  fireplace  or 
a  furnace.  The  only  partial  exception  that  has  come  to  the 
author's  notice  is  the  case  of  those  houses  in  the  interior 
of  the  United  States  in  which  natural  gas  is  used  for  cook- 


342  DISINFECTION 

ing  and  heating.  As  this  produces  no  ashes,  it  is  said  by 
housekeepers  in  these  neighborhoods  to  be  a  matter  of 
some  inconvenience  to  get  rid  of  dust  and  wastes  which 
in  other  parts  of  the  world  are  usually  thrown  into  the 
stove  or  the  furnace  and  burned. 

Boiling  water  is  an  excellent  disinfectant,  which  is  usually 
available  in  almost  every  household.  If  soap  be  added  to 
it,  the  chemical  effect  of  the  alkali  is  added  to  the  physical 
effect  of  the  heat,  and  better  disinfection  is  brought  about. 
The  scrubbing  of  a  floor  with  hot  soapsuds  is  an  admirable 
though  primitive  way  of  removing  infection,  and  one  of  the 
best  mechanical  disinfectants  is  probably  washing  followed 
by  thorough  rubbing,  which  shall  dislodge  infectious  mate- 
rials from  the  surface  of  the  body,  from  clothing,  walls,  etc. 

The  first  of  the  chemical  disinfectants  to  receive  general 
attention  was  carbolic  acid,  which  was  introduced  shortly  after 
Pasteur's  investigations  referred  to  in  the  second  chapter. 
This,  though  still  held  in  high  popular  esteem,  has  been 
largely  superseded  by  more  effective  germicides,  among 
which  we  may  mention  corrosive  sublimate  and  formic 
aldehyde  (formalin).  A  great  variety  of  special  disinfec- 
tants is  now  upon  the  market;  but  this  is  not  the  place 
to  consider  their  merits.  One  of  the  simplest  and  most 
useful  of  household  disinfectants  is  the  milk  of  lime, 
freshly  made;  and  even  when  stale,  lime-water  is  still  a 
valuable  disinfectant. 

§  9.  —  Germicidal-Efficiency  Tests 

In  order  to  test  the  efficiency  of  any  particular  germicides, 
careful  precautions  must  be  taken.  It  is  not  enough  to  mix 
a  measured  portion  of  the  germicide  with  a  liquid  containing 
bacteria,  and  then  to  observe  whether  or  not  a  portion  of  the 
mixture  will  grow  upon  the  ordinary  bacterial  soils,  such  as 
gelatine  or  agar,  for  in  this  case  some  of  the  germicide  may 
have  been  carried  over,  and  though  dilute,  may  nevertheless 


SPECIAL  DISINFECTANTS  AND  GERMICIDES       343 

continue  to  act  over  a  long  period.  Various  methods  have 
been  devised  in  order  to  avoid  this  fundamental  difficulty ; 
but  none  of  them  are  wholly  satisfactory.  A  discussion  of 
the  question  may  be  found  in  a  paper  by  the  author  entitled 
"  Germicidal  Efficiency  Test  of  a  Disinfectant  to  be  used 
in  Railway  Sanitation."  Technology  Quarterly,  Vol.  IV, 
No.  2.  Boston,  1893. 

§  10.  —  Present  State  of  the  Art  of  Disinfection 

Under  state  and  municipal  control  the  art  of  disinfection 
has  now  reached  a  considerable  degree  of  efficiency.  It  is 
practicable  by  means  of  steam,  or  the  vapors  of  particular 
substances  such  as  sulphurous  acid  or  formalin,  to  disinfect 
with  some  success  buildings,  ships,  apartments,  furniture 
and  the  like,  but  much  still  needs  to  be  done  upon  this 
subject.  Those  who  desire  to  pursue  this  part  of  the  sub- 
ject are  referred  to  Dr.  C.  V.  Chapin's  valuable  work  on 
"  Municipal  Sanitation  in  the  United  States."  Providence, 
R.I.,  1901. 

§  ii.  —  Intestinal  Disinfection 

An  ingenious  procedure  has  been  suggested  in  the  case 
of  certain  infectious  diseases,  especially  such  as  affect  the 
intestines  or  other  portions  of  the  alimentary  canal,  namely, 
that  it  may  be  possible  to  disinfect  the  alimentary  canal  or 
other  special  portions  of  the  body.  In  the  case  of  typhoid 
fever,  for  example,  it  is  suggested  that  substances  might 
be  swallowed  which,  while  passing  through  the  mouth  and 
stomach,  should  be  harmless,  but  on  reaching  the  small 
intestine  should  become  decomposed  or  converted  into 
antiseptics  or  even  into  disinfectants  powerful  enough  to 
destroy  the  micro-organisms  of  disease  yet  not  powerful 
enough  to  damage  the  general  organism.  In  certain  cases 
of  cystitis,  believed  to  be  due  to  the  typhoid  bacillus,  it  is  be- 
lieved that  substances  may  even  now  be  introduced  into  the 
body  which  on  reaching  the  bladder  actually  become  effec- 


344  DISINFECTION 

tive  disinfectants  capable  of  destroying  the  germs  of  the 
disease.  If  the  hopes  raised  by  these  suggestions  prove  to 
be  justified,  internal  disinfection  of  special  portions  of  the 
body  will  then  have  realized  Professor  Huxley's  fancy  of 
the  cunningly  devised  torpedo  which  when  swallowed  shall 
find  its  way  to  the  diseased  point  of  the  organism  and  by 
exploding  there  do  effective  work  in  destroying  the  germs 
of  disease. 


PART  III 

APPENDIX 


APPENDIX 

ON   SOME  POPULAR   BELIEFS  AS  TO   CERTAIN  SPE- 
CIAL AND  PECULIAR  CAUSES  OF  DISEASES 

"  Depend  upon  it,  in  all  long-established  practices  or  spiritual  formu- 
las there  has  been  some  living  truth." — J.  A.  FROUDE. 

§  I. —  Vagaries  of  Pseudo-"  Sanitary  Science" 

THERE  is  perhaps  no  subject  in  which  serious  errors  are  more 
prevalent  than  in  popular  hygiene.  This  is  doubtless  due  to 
the  fact  that  while  disease  has  long  been  only  too  familiar  and 
well  known,  any  accurate  knowledge  of  the  nature  and  causes  of 
disease  is  comparatively  modern.  With  the  advent  of  rational 
conceptions  of  the  nature  and  cause  of  diseases,  more  or  less 
misunderstanding  and  misconception  of  the  application  of  these 
notions  was  perhaps  inevitable.  It  seems  worth  while,  therefore, 
to  dwell  briefly  upon  some  of  the  more  widespread  of  the  falla- 
cious notions  or  half-truths  of  sanitary  science,  and  to  define 
explicitly  the  present  attitude  of  the  best  opinion  of  the  time  in 
regard  to  certain  subjects  relating  to  the  public  health,  commonly 
misunderstood  or  misinterpreted. 

§  2.  —  The  Belief  in  Dangers  from  Sewer  Gas 

It  is  commonly  believed  that  much  sickness  is  directly  caused 
by  the  emanations  of  gases  from  sewers,  drains,  cesspools  or 
other  receptacles  for  sewage  and  similar  foul  or  decomposing  sub- 
stances. This  belief  even  goes  so  far  popularly,  and  sometimes 
professionally,  as  to  serve  as  the  all-sufficient  explanation  for  the 
occurrence  of  certain  specific  diseases,  such  as  typhoid  fever, 
dysentery,  diphtheria  and  scarlet  fever. 

347 


348  APPENDIX 

Closely  examined,  the  belief  in  the  efficiency  of  sewer  gas 
as  the  cause,  not  only  of  general,  but  also  of  specific,  disease 
appears  to  rest  upon  the  idea  that  in  some  way  or  other 
poisonous  gases,  after  having  been  formed  in  sewers,  cesspools 
and  the  like  by  active  decomposition  of  the  foul  substances 
therein,  escape  into  the  air,  and  being  inhaled,  either  by  virtue 
of  their  chemical  character  or  by  means  of  micro-organisms,  for 
which  they  are  a  vehicle,  produce  insidious  general  poisoning  or 
specific  disease.  It  is  very  seldom,  however,  that  the  sewer-gas 
theory  of  disease  is  thus  explicitly  and  clearly  defined.  More 
often  it  takes  the  form  of  the  simple  statement  or  belief  that 
typhoid  fever,  dysentery,  diphtheria  or  malaria,  are  directly  pro- 
duced by  broken  drains ;  and  it  is  this  form  chiefly  of  the  theory 
or  belief  which  requires  to  be  corrected.  Sometimes  the  sewer- 
gas  theory  takes  a  more  general  form,  vaguely  hinting  at  obscure 
but  powerful  influences,  as,  e.g,  in  the  following :  "  Now  here  is  a 
removable  cause  of  death.  These  gases,  which  so  many  thousands 
of  persons  are  daily  inhaling,  do  not,  it  is  true,  in  their  diluted 
condition,  suddenly  extinguish  life.  ...  In  their  diluted  state 
as  they  rise  from  so  many  cesspools  and  taint  the  atmosphere  of 
so  many  houses  they  form  a  climate  congenial  for  the  multiplication 
of  epidemic  disorders,  and  operate  beyond  all  known  influences 
of  this  class  in  impairing  the  chances  of  life."  (SiMON,  1849.) 

The  facts  with  regard  to  sewer  gas,  and  the  part  which  it  plays 
in  the  causing  of  disease,  appear  at  present  to  be  as  follows : 
In  the  first  place,  there  is  reason  to  believe  that  the  dangers  of 
sewer  gas  have  been  very  much  exaggerated.  There  is  no  doubt, 
of  course,  that  sewage  is  a  decomposing  liquid,  and  that  it  may, 
and  often  does,  contain  the  germs  of  specific  diseases.  But,  on 
the  other  hand,  the  facts  that  workmen  frequently  spend  much  of 
their  time  in  sewers  with  impunity,  or  work  upon  or  about  sewage 
in  sewage-purification  works  or  on  sewage  farms,  seem  to  show 
that  experience  does  not  confirm  the  idea  that  the  gases  emanat- 
ing from  sewage  are  always  or  necessarily  dangerous.  Further- 
more, careful  chemical  and  bacteriological  examinations  of  the 
air  of  sewers  have  shown,  not  only  that  dangerous  gases  cannot 
ordinarily  be  detected  in  such  air,  but  even  that  sewer  air  is  sin- 
gularly free  from  micro-organisms.  A  little  reflection  will  show 


DANGER  FROM   SEWER  GAS  349 

that  these  results  might  have  been  expected,  for  decomposition 
of  sewage  in  the  sewers  is  seldom  very  advanced  or  extensive; 
while  the  air  of  sewers,  being  very  quiet,  ought  to  contain  few 
bacteria. 

If,  now,  we  turn  to  stagnant  sewage,  such  as  might  result  from 
broken  drains,  or  such  as  commonly  exists  in  cesspools,  we  may 
reasonably  expect  to  find  more  dangerous  and  more  concentrated 
gases.  We  may  even  suppose  that  these  are  poisonous,  and  that, 
finding  their  way  into  human  habitations,  they  are  capable  of 
producing  sickness.  There  is  no  reason  to  doubt  that  some  cases 
of  sickness  have  in  fact  thus  arisen,  and  to  this  extent  the  belief 
in  sewer  gas  as  a  cause  of  disease  is  probably  sound.  In  such 
cases,  however,  the  sickness  may  be  expected  to  take  either  the 
form  of  sudden,  sharp  attacks,  suggestive  of  poisoning,  or  else 
the  form  of  malaise  and  a  general  lowering  of  the  vital  resistance, 
lassitude,  weakness,  etc. 

While  thus  freely  granting  the  possible  efficiency  of  sewer  gas 
as  a  general  poison  and  depressant,  we  are  very  far  from  allowing 
the  remaining  and  more  popular  form  of  the  belief  in  sewer  gas, 
namely,  that  it  is  capable  of  directly  producing  specific  diseases, 
such  as  typhoid  fever  and  diphtheria,  which  absolutely  require 
for  their  genesis  the  introduction  into  the  body  of  their  own 
peculiar  germs.  The  popular  belief  must  presuppose  that  sewer 
gas  is  somehow  a  vehicle  for  these  particular  germs,  which  are 
lifted  by  it  from  the  sewers  or  cesspools,  and  conveyed  with  it 
into  the  alimentary  or  respiratory  passages  of  the  victim;  and 
it  is  this  part  of  the  theory  which  cannot  readily  be  allowed  by 
the  student  of  sanitary  science.  (See  quotation  from  Budd,  be- 
yond, pp.  354-355-)  The  reader  who  wishes  to  pursue  this  sub- 
ject further  is  referred  to  the  valuable  treatise  by  H.  A.  Roechling, 
C.E.,  entitled  "  Sewer  Gas  and  its  Influence  upon  Health."  Lon- 
don, Biggs  and  Co.,  1898. 

§  $.—  The  Belief  in  Danger  from    Well  Waters 

One  of  the  most  widespread  of  the  popular  sanitary  beliefs  of 
the  time  is  that  which  regards  with  suspicion  the  waters  of  ordinary 
domestic  wells.  This  is  a  comparatively  novel  point  of  view,  for 


350  APPENDIX 

until  within  the  memory  of  the  present  generation  the  domestic 
well  was  regarded  as  one  of  the  most  valuable  adjuncts  of  all 
well-regulated  houses.  Even  to-day  most  country  people,  when 
informed  by  pseudo-sanitarians  that  grave  danger  resides  in  the 
family  well,  from  which  perhaps  several  generations  of  their  ances- 
tors have  drunk  with  satisfaction  and  benefit,  refuse  to  entertain 
the  idea  that  serious  danger  can  possibly  exist  in  anything  so 
thoroughly  tested  and  so  long  highly  regarded. 

There  is  probably  some  truth  in  both  points  of  view.  The  caus- 
ation of  cholera  by  the  Broad  Street  well,  referred  to  in  a  previous 
chapter  (p.  1 70),  and  other  equally  undoubted  examples  of  infec- 
tion from  polluted  wells,  have  led  to  the  generalization  that  serious 
danger  often  lurks  in  well  waters.  On  the  other  hand,  there  are 
in  existence  innumerable  examples  of  domestic  wells  which  have 
faithfully  ministered  to  the  wants  of  families  through  long  and 
successive  generations;  so  that  while  it  is  true  that  well  waters 
are  sometimes  dangerous,  it  is  no  less  true  that  they  are  by  no 
means  always  dangerous. 

The  popular  confusion  of  the  matter  has  probably  arisen  through 
inaccurate  reasoning  as  to  the  ways  in  which  wells  may  become 
infected.  The  common  form  of  theory  in  this  particular  —  at 
least  in  the  United  States  —  is  essentially  as  follows :  Inasmuch 
as  ground  water  readily  moves  through  the  earth,  and  inasmuch, 
further,  as  polluting  materials  are  often  deposited  upon  or  within 
the  earth,  these  may  be  borne  by  the  underground  water,  which 
feeds  the  well,  from  a  place  of  deposit  upon  or  within  the  earth 
into  the  well  itself.  The  picture  which  may  readily  be  drawn  of 
such  contamination,  or,  as  it  is  generally  called,  "leaching,"  through 
the  earth,  is  simple ;  and  many  more  or  less  popular  works  upon 
hygiene  have  now  for  some  years  given  illustrations  showing  the 
possible  route  taken  by  infectious  materials,  either  from  the  surface 
of  the  earth,  as,  for  example,  from  heaps  of  night  soil  or  other  ex- 
creta carelessly  deposited  there,  or  more  often  from  leaky  cesspools 
and  the  like,  which  may  readily  be  so  disposed  in  pictures,  or  in 
fact,  as  to  appear  to  furnish  pabulum  for  wells  in  the  neighborhood. 

On  the  other  hand,  comparatively  little  is  said  in  such  cases 
about  the  dangers  of  infection  from  the  top  of  the  well.  In  the 
opinion  of  the  author,  however,  it  is  precisely  this  source  of  infec- 


DANGER  FROM  WELL  WATERS 


351 


tion  which  is  most  to  be  dreaded,  and,  as  a  rule,  is  most  effective ; 
for  any  one  who  reflects  upon  the  filtering  powers  of  the  earth 
must  readily  perceive  how  unlikely  it  is  that  disease  germs  shall 
be  able  to  survive  in,  and  pass  even  a  few  feet  through  soil  beyond, 
a  leaky  cesspool ;  and  that  filtration  and  purification  do,  in  fact, 
occur  in  ordinary  domestic  wells  located  in  apparently  dangerous 
proximity  to  barnyards  and  privies,  is  well  shown  by  the  chemical 
and  bacterial  composition  of  the  waters  collected  from  them. 

Excepting  those  cases  in  which  cracks  or  fissures  in  the  earth 
allow  direct  communication  between  polluting  sources  and  wells 
of  drinking  water,  the  author  is  strongly  of  the  opinion  that  in 
most  cases  in  which  infection  exists  in  wells,  the  polluting  mate- 
rial has  found  its  way  in  from  the  top.  Some  examples  of  this 
kind  have  been  given  in  a  previous  chapter,  one  of  the  most 
famous  being  the  celebrated  Caterham  case  (p.  191),  in  which 
the  infection  of  a  well  in  the  chalk,  by  a  workman  who  had 
gone  in  by  the  top,  led  to  an  alarming  epidemic  among  persons 
supplied  with  the  well  water. 

When  one  reflects  on  the  carelessness  with  which  wells  used 
as  sources  of  drinking  water  are  exposed  to  the  access  of  filth 
from  the  top,  such  wells  often  being  only  loosely  covered  by 
planks,  between  which  grasshoppers,  toads  or  leaves  frequently 
make  their  way,  it  is  easy  to  see  that  from  the  boots  of  work- 
men, or  from  children  playing  on  the  planks,  or  from  poultry 
walking  about  and  carrying  infection  on  their  feet,  pollution  may 
readily  take  place.  The  author  on  one  occasion  noticed,  for 
example,  the  following  state  of  affairs.  On  a  farm  in  an  inland 
Massachusetts  town  were  people  sick  with  typhoid  fever.  The 
privy  was  freely  open  beneath  and  behind,  and  fowls  were  walk- 
ing about  under  it.  The  same  fowls  a  little  later  were  seen 
moving  aimlessly  and  repeatedly  about  upon  the  old  and  worn 
pieces  of  planking  which  loosely  covered  the  domestic  well  top. 
The  well  was  provided  with  a  pump,  and  in  the  water  drawn  by 
the  pump  milk  cans  were  washed  and  rinsed  before  receiving  milk 
to  be  shipped  for  the  Boston  market.  There  was  reason  at  the 
time  to  suspect  that  certain  cases  of  typhoid  fever  in  a  part  of 
the  distant  city  among  the  users  of  this  milk  had  been  caused  by 
milk  from  this  farm.  Whether  this  was  the  case  or  not,  the  local 


352  APPENDIX 

conditions  were  certainly  such  as  to  allow  ready  pollution  of  the 
well  water. 

The  truth  in  regard  to  the  dangers  of  well  waters  appears  to  be, 
that  if  the  wells  are  thoroughly  protected  at  the  top  from  the 
entrance  of  filth,  they  are  as  a  rule,  from  the  disease-producing 
point  of  view,  unimpeachable,  being  perhaps  indeed  polluted  with 
purified  sewage  but  not  often  actually  infected  with  the  germs  of 
disease.  Such  waters  should  be  regarded  with  suspicion  and  care- 
fully avoided,  but  yet,  in  the  majority  of  cases,  cannot  reasonably 
be  considered  as  a  ready  vehicle  of  disease. 

"And  I  would  add  that  certain  observations  which  I  made 
recently  in  a  fever-stricken  village  .  .  .  have  induced  me  to 
think  that  of  the  two  recognized  foci  for  infection  [in  typhoid 
fever],  the  bespattered  privy  and  the  contaminated  well,  the 
former  may  be  the  one  which  is  more  commonly  at  work."  — 
PROFESSOR  GEORGE  ROLLESTON,  M.D.,  F.R.S..  The  Lancet,  March 
6,  1869. 

§  4.  —  The  Belief  in  Dangers  from  Broken  Drains 

Another  popular  belief  which  requires  careful  examination  is 
that  of  the  efficacy  of  broken  drains  as  causes  of  disease.  From 
what  has  been  said  under  the  first  section  of  this  chapter  in  regard 
to  sewer  gas,  the  reader  will  surmise  that  the  author  attaches  but 
little  importance  to  sewers  as  direct  sources  of  infectious  disease. 
A  broken  drain  may,  and  undoubtedly  often  does,  yield  more  or 
less  of  objectionable  and  sometimes  poisonous  gases,  but  in  the 
present  state  of  our  knowledge  of  the  aetiology  of  disease  it  is  very 
difficult,  if  not  almost  impossible,  to  understand  how  the  accumu- 
lation of  sewage  in  a  cellar,  or  leakages  of  sewage  from  broken 
drains,  or  the  escape  of  gases  from  such  drains,  can  possibly 
provoke  infectious  disease. 

The  belief  in  question  has  doubtless  arisen,  naturally  enough, 
from  a  certain  number  of  cases  of  coincidence  between  serious 
illness  in  the  house  and  serious  breaks  in  house  drains.  A  well- 
known  case  of  this  kind  occurred  in  Boston.  The  children  of  a 
family  sickened  and  died  from  diphtheria ;  and  inasmuch  as  on 
examination  broken  drains  were  discovered  in  the  basement,  the 
conclusion  was  immediately  drawn  that  the  drains  were  the  cause 


DANGER  FROM  BROKEN  DRAINS       353 

of  the  disease.  In  many  houses,  however,  broken  drains  occur, 
and  even  temporary  accumulations  of  sewage  matters,  without  any 
unfavorable  consequences  making  their  appearance.  In  the  pres- 
ent state  of  sanitary  science  it  is  far  more  reasonable  to  suppose 
that  the  diphtheria  was  brought  into  the  house  by  milk  or  other 
uncooked  foods,  or  by  a  servant  suffering  from  a  mild  form  of  the 
disease,  or  in  some  other  unsuspected  way,  than  to  attribute  it 
to  the  occult  influence  of  broken  drains.  Here,  again,  the  gases 
arising  from  leaks  and  breaks  may  have  a  toxic  effect,  and  thus 
lower  vital  resistance  and  increase  susceptibility.  To  this  extent, 
and  probably  to  this  extent  only,  broken  drains  are  "  sources  "  of 
disease. 

§  5.  —  The  Belief  in  Bad  Smells  as  Causes  of  Disease 

There  can  be  no  doubt  that  evil  odors  may  produce  temporary 
sickness.  The  inhabitants  of  Millbury,  in  the  suit  of  the  latter 
town  against  the  city  of  Worcester,  Mass.,  testified  that  they  had 
been  sickened  by  the  smells  arising  from  the  polluted  Blackstone 
River ;  and  the  smell  arising  from  tidal  flats,  covered  at  high  tide 
by  sewage-polluted  waters  and  laid  bare  at  low  tide,  may  certainly 
be  nauseous.  On  the  other  hand,  there  is  no  evidence  whatever 
that  typhoid  fever  or  other  infectious  diseases  can  be  directly 
caused  in  this  way,  so  that  while  bad  smells  may  be  regarded  as 
significant  of  putrefaction,  decay,  or  even  disease,  and  therefore 
useful  warnings  of  trouble,  they  cannot  in  the  present  state  of  our 
knowledge  be  regarded  as  true  sources  of  infectious  disease.  If, 
however,  the  vital  resistance  be  lowered  by  such  smells,  they  may 
favor,  even  if  they  cannot  cause,  disease.  But  it  does  not  follow 
that  bad  smells  do  necessarily,  though  they  certainly  may,  lower 
the  vital  resistance,  at  least  so  far  as  this  can  be  measured  by  the 
death-rate.  Thackrah,  the  founder  of  industrial  hygiene,  in  his 
famous  work,  published  in  1831,  makes  the  following  statement :  — 

"  The  atmosphere  of  the  slaughter-house,  though  sufficiently  disgusting  to 
the  nose,  does  not  appear  to  be  at  all  injurious  to  health.  The  mere  odors  of 
animal  substances,  whether  fresh  or  putrid,  are  not  apparently  hurtful;  indeed, 
they  seem  to  be  often  decidedly  useful." 

One  of  the  most  famous  stinks  that  has  been  recorded  —  if  not 
the  most  famous  —  was  that  which  arose  from  the  Thames,  in 

2A 


354  APPENDIX 

London,  in  1858  and  1859.     Nevertheless,  as  has  been  insisted 
by  Dr.  Budd,  no  very  serious  results  followed. 

"  The  need  of  some  radical  modification  in  the  view  commonly  taken  of  the 
relation  which  subsists  between  typhoid  fever  and  sewage  was  placed  in  a  very 
striking  light  by  the  state  of  the  public  health  in  London,  during  the  hot 
months  of  1858  and  1859,  when  the  Thames  stank  so  badly. 

"  The  late  Dr.  McWilliam  pointed  out  at  the  time,  in  fitting  and  emphatic 
terms,  the  utter  inconsistency  of  the  facts  with  the  received  notions  on  the 
subject.  Never  before  had  Nature  laid  down  the  data  for  the  solution  of  a 
problem  of  this  kind  in  terms  so  large,  or  wrought  them  out  to  so  decisive  an 
issue.  As  the  lesson  then  taught  us  seems  to  be  already  well-nigh  forgotten, 
I  may,  perhaps,  be  allowed  to  recall  some  of  its  most  salient  points. 

"  The  occasion,  indeed,  as  already  hinted,  was  no  common  one.  An  extreme 
case,  a  gigantic  scale  in  the  phenomena,  and  perfect  accuracy  in  the  registra- 
tion of  the  results  —  three  of  the  best  of  all  the  guarantees  against  fallacy  — 
were  combined  to  make  the  induction  sure.  For  the  first  time  in  the  history  of 
man,  the  sewage  of  nearly  three  millions  of  people  had  been  brought  to  seethe 
and  ferment  under  a  burning  sun,  in  one  vast  open  cloaca  lying  in  their 
midst. 

"  The  result  we  all  know.  Stench  so  foul,  we  may  well  believe,  had  never 
before  ascended  to  pollute  this  lower  air.  Never  before,  at  least,  had  a  stink 
risen  to  the  height  of  an  historic  event.  Even  ancient  fable  failed  to  furnish 
figures  adequate  to  convey  a  conception  of  its  thrice-Augean  foulness.  For 
many  weeks  the  atmosphere  of  Parliamentary  committee-rooms  was  only  ren- 
dered barely  tolerable  by  the  suspension  before  every  window  of  blinds  satu- 
rated with  chloride  of  lime,  and  by  the  lavish  use  of  this  and  other  disinfectants. 
More  than  once,  in  spite  of  similar  precautions,  the  law  courts  were  suddenly 
broken  up  by  an  insupportable  invasion  of  the  noxious  vapor.  The  river 
steamers  lost  their  accustomed  traffic,  and  travellers  pressed  for  time  often 
made  a  circuit  of  many  miles  rather  than  cross  one  of  the  city  bridges. 

"  For  months  together,  the  topic  almost  monopolized  the  public  prints. 
Day  after  day,  week  after  week,  the  Times  teemed  with  letters  filled  with  com- 
plaint, prophetic  of  calamity,  or  suggesting  remedies.  Here  and  there,  a  more 
than  commonly  passionate  appeal  showed  how  intensely  the  evil  was  felt  by 
those  who  were  condemned  to  dwell  on  the  Stygian  banks.  At  home  and 
abroad,  the  state  of  the  chief  river  was  felt  to  be  a  national  reproach.  '  India 
is  in  revolt,  and  the  Thames  stinks,'  were  the  two  great  facts  coupled  together 
by  a  distinguished  foreign  writer,  to  mark  the  climax  of  a  national  humiliation. 
But  more  significant  still  of  the  magnitude  of  the  nuisance  was  the  fact  that 
five  millions  [of  pounds]  of  money  were  cheerfully  voted  by  a  heavily  taxed  com- 
munity to  provide  the  means  for  its  abatement.  With  the  popular  views  as  to 
the  connection  between  epidemic  disease  and  putrescent  gases,  this  state  of 
things  naturally  gave  rise  to  the  worst  forebodings. 

"  Members  of  Parliament  and  noble  lords,  dabblers  in  sanitary  science,  vied 


AN   HISTORIC   STINK 


355 


with  professional  sanitarians  in  predicting  pestilence.  If  London  should  hap- 
pily be  spared  the  cholera,  decimation  by  fever  was,  at  least,  a  certainty.  The 
occurrence  of  a  case  of  malignant  cholera  in  the  person  of  a  Thames  waterman 
early  in  the  summer  was  more  than  once  cited  to  give  point  to  these  warn- 
ings, and  as  foreshadowing  what  was  to  come.  Meanwhile,  the  hot  weather 
passed  away;  the  returns  of  sickness  and  mortality  were  made  up,  and,  strange 
to  relate,  the  result  showed,  not  only  a  death-rate  below  the  average,  but,  as  the 
leading  peculiarity  of  the  season,  a  remarkable  diminution  in  the  prevalence  of 
fever,  diarrhcea,  and  the  other  forms  of  disease  commonly  ascribed  to  putrid 
emanations. 

"  After  describing  in  scientific  and  forcible  terms  the  unprecedented  state 
of  the  river,  Dr.  Letheby  adds :  '  With  all  this  condition  of  the  Thames,  how- 
ever, the  health  of  the  metropolis  has  been  remarkably  good.  In  the  corre- 
sponding period  of  last  year  (t.e.  of  the  year  1857),  the  cases  of  fever,  diarrhcea, 
and  dysentery,  attended  in  the  city  by  the  medical  officers  of  the  unions, 
amounted  to  293  of  the  former,  and  181  of  the  latter;  but  during  the  past 
quarter  (i.e.  the  quarter  of  intolerable  stench),  they  were  only  202  of  the 
former,  and  93  of  the  latter ! ' 

"  The  testimony  of  Dr.  Me  William,  as  medical  supervisor  of  the  waterguard 
and  waterside  custom-house  officers,  is  still  more  to  the  point.  The  former, 
to  the  number  of  more  than  eight  hundred,  '  may  be  said  to  live  on  the  river, 
or  in  the  docks,  in  ships,  or  in  open  boats;  and  the  latter,  numbering  upward 
of  five  hundred,  are  employed  during  the  day  in  the  docks,  or  at  the  various 
wharves  of  the  bonded  warehouses  on  each  side  of  the  river.'  After  stating 
that  the  amount  of  general  sickness  among  these  men  was  below  the  average 
of  the  three  preceding  years,  and  considerably  below  that  of  the  forms  of  dis- 
ease (including  diarrhoea,  choleraic  diarrhcea,  dysentery,  etc.),  which,  in  this 
country,  noxious  exhalations  are  commonly  supposed  to  originate,  we  find  the 
additions  during  the  four  hot  months  of  the  year  from  this  class  of  complaints 
26.3  below  the  average  of  the  corresponding  period  of  the  three  previous 
years,  and  73  per  cent  less  than  those  of  1857.  In  another  passage  this  dis- 
tinguished physician  says :  '  It  is  nowhere  sustained  by  evidence  that  the 
stench  from  the  river  and  docks,  however  noisome,  was  in  any  way  productive 
of  disease.  On  the  contrary,  there  was  less  disease  of  that  form  to  which  foul 
emanations  are  supposed  to  give  rise  than  usual. 

"  Before  these  inexorable  figures  the  illusions  of  half  a  century  vanish  in  a 
moment."  —  WILLIAM  BUDD,  Typhoid  Fner,  its  Nature,  Mode  of  Spreading 
and  Prevention,  pp.  148-151.  London,  1873. 

Dr.  Ord  reported  to  the  Privy  Council  in  1859  that  in  1858  (the 
year  of  the  worst  stench)  steamboat  men  on  the  Thames  suffered 
severely  from  languor,  headache,  sore  throat,  nausea,  giddiness, 
mental  confusion,  etc.  (in  other  words  from  symptoms  of  poisoning). 
In  1859  the  river  was  much  better,  and  very  few  such  symptoms 
occurred  :  "  The  greater  weekly  mortality  has  not  coincided  with 


356  APPENDIX 

the  greater  development  of  the  stench,  our  most  ready  measure  of 
the  foulness  of  the  stream.  ...  In  both  years  the  presence  of 
sulphuretted  hydrogen  in  the  river  atmosphere  was  shown  by  the 
rapid  blackening  of  paper  soaked  in  solutions  of  lead,  and  by  the 
discoloration  of  the  paint  of  vessels."  —  Second  Report,  Medical 
Officer  of  the  Privy  Council,  for  1859,  p.  55.  London,  1860. 

§  6.  —  Is  Consumption  Inherited? 

The  discovery  by  Koch,  in  1882,  that  tuberculosis  is  accompa- 
nied, and  apparently  originated,  by  a  specific  bacillus,  has  caused 
the  popular  belief  that  consumption  is  hereditary  to  be  seriously 
questioned.  The  results  of  numerous  experiments  made  by  com- 
petent observers  have  tended  to  show  that  the  germs  of  the  disease 
are  not  often  conveyed  directly  from  parent  to  offspring,  while  the 
observations  of  pathologists  have,  as  a  rule,  tended  to  indicate 
that  new-born  children  of  consumptive  parents  are  free  from  all 
signs  of  the  disease.  On  the  other  hand,  no  belief  probably  is 
more  firmly  rooted  in  the  human  race  than  that  "consumption 
runs  in  families,"  and  is  peculiarly  an  hereditary  disease.  How, 
it  may  well  be  asked,  can  these  opposing  results  of  experience  and 
experiment  be  harmonized  ?  The  answer  is  simple.  If  we  assume, 
in  accordance  with  the  results  of  experiment,  that  the  germs  them- 
selves are  not  ordinarily  inherited,  we  are  not  thereby  prevented 
from  supposing  that  those  special  constitutional  qualities  which 
allowed  the  disease  to  prevail  in  one  generation  are  inherited,  so 
that,  while  the  germs  themselves  may  not  be  carried  on  directly 
from  generation  to  generation,  a  soil  suitable  for  their  develop- 
ment and  multiplication  is  nevertheless  inherited,  and  only  requires 
to  be  sown  with  the  germs  in  question  in  order  to  give  rise  to  the 
disease.  In  other  words,  while  the  disease  itself  and  its  agents 
are  ordinarily  not  inherited,  a  predisposition  to  the  disease,  a  ten- 
dency, a  weakness,  or  a  condition  favorable  to  the  disease,  may 
be  thus  derived. 

For  example,  a  child  of  consumptive  parentage  may  conceivably 
be  born  absolutely  free  from  the  germs  of  disease,  yet  of  such 
constitution  as  to  be  highly  susceptible  to  them  ;  and  it  is  easy  to 
see  how,  even  within  a  few  days,  such  a  child  may  become  infected 


TUBERCULOSIS   PROBABLY   NOT   INHERITED       357 

from  the  milk  or  the  lips  of  a  tuberculous  mother.  This  solution 
of  the  problem  is  interesting,  as  allowing  place  both  for  the  instinc- 
tive experience  of  the  race  which  seems  to  show  that  the  disease 
is  inherited,  while  in  reality  only  showing  that  the  disease  runs  in 
families,  such  "  running  "  being  due,  not  to  the  inheritance  of  the 
disease  itself,  but  to  the  action  of  contagion  from  infected  elders 
upon  susceptible  offspring  which  have  a  tendency  or  predisposition 
to  the  disease. 


§  7.  —  The  Probable  Truth  about  Endemic  Disease 

One  of  the  common  phrases  of  sanitary  science,  especially  in 
popular  discussions,  is  that  which  describes  disease  as  "  endemic  " 
in  certain  localities.  What  is  meant  by  the  expression  is  that  the 
disease  appears  to  have,  in  the  localities  mentioned,  a  local  and 
permanent  residence.  Expressions  of  this  kind,  however,  at  least 
when  applied  to  infectious  disease,  have  very  little  value.  It  was 
formerly  said,  for  example,  that  typhoid  fever  was  "  endemic  "  in 
Lowell  and  Lawrence,  by  which  was  meant  the  obvious  fact  that 
it  was  always  to  be  found  there,  with  the  added  implication  that 
there  was  something  peculiar  in  the  local  conditions,  such,  for 
example,  as  a  special  soil,  ground  water,  or  other  local  condition, 
which  made  these  cities  an  especially  favorable  dwelling-place  for 
the  disease. 

The  fact  was  undoubtedly  correct :  typhoid  fever  was  always 
or  nearly  always  present;  but  the  implication  was  incorrect. 
There  was  nothing  in  Lowell  or  Lawrence  essentially  different 
in  respect  to  soil  or  people  or  any  other  particular  (with  one 
exception)  from  the  conditions  prevailing  in  Concord,  Man- 
chester, Nashua  or  Haverhill,  neighboring  cities  in  the  same 
valley.  The  one  exception  was  the  water  supply,  by  which  the 
germs  of  typhoid  fever  were  distributed  among  the  citizens. 
Once  this  element  of  infection  was  removed,  the  disease  nearly 
disappeared,  and  ceased  to  be  endemic.  As  a  matter  of  fact,  it 
had  never  been  endemic,  but  was  rather  constantly  epidemic. 

Careful  investigation  is  required,  therefore,  in  any  particular 
case  before  we  are  justified  in  concluding  that  any  particular  dis- 
ease is  endemic,  i.e.  at  home  in  nature  in  any  particular  locality. 


358  APPENDIX 

Such  cases  do  perhaps  exist,  as,  for  example,  in  the  case  of 
Asiatic  cholera  in  Calcutta,  and  of  malaria  in  the  Roman  cam- 
pagna ;  but  recent  advances  in  the  study  of  the  latter  disease  have 
thrown  grave  doubt  on  its  necessary  endemicity  even  in  the  cam- 
pagna,  and  such  cases  are  nowadays  to  be  regarded  as  established 
only  after  the  most  careful  investigation. 

§  8.  —  The  Belief  in  Dangers  from  Atmospheric  and 
Telluric  Disturbances 

One  of  the  popular  beliefs  which  meets  the  student  of  sanitary 
science  when  he  undertakes  to  discover  the  sources  of  epidemic 
disease  is  an  indefinite  and  occult  feeling  that  there  has  been 
something  mysterious  and  yet  influential  in  the  earth  or  the  air 
sufficient  to  account  for  the  prevalence  of  the  epidemic  in  ques- 
tion, if  there  happens  to  be  one.  The  author,  in  the  course  of  his 
studies  of  typhoid  fever,  for  example,  has  frequently  been  told  that 
in  the  opinion  of  such  and  such  persons  the  disease  prevailing  at 
the  moment  was  due  to  "a  late  spring,"  or  "a  hard  winter,"  or 
to  the  turning  up  of  the  soil  in  the  neighborhood,  or  to  prolonged 
cloudy  weather,  or  some  other  similar  indefinite  or  obscure  cause, 
when  perhaps  in  reality  the  true  cause  was  an  infection  of  milk 
supply  or  water  supply,  or  a  simple  case  of  secondary  infection 
from  person  to  person. 

This  form  of  belief  is  probably  the  survival  of  a  very  ancient 
and  natural  tendency  in  the  human  race  to  connect  any  unusual 
yet  well-remembered  event  with  other  unusual  or  especially  dis- 
astrous phenomena  antecedent  to  the  first  in  time,  and  marks 
an  interesting  reversion  to  theories  commonly  accepted  in  the 
childhood  of  the  race,  but  long  since  outgrown.  Nothing  better 
illustrates  the  fundamental  value  of  the  germ  theory  of  disease 
in  placing  upon  definite  material  particles  the  responsibility  for 
causation,  than  the  ease  with  which  such  primitive  theories  may 
by  its  use  be  discredited.  Sanitary  science  readily  allows  the  direct 
physiological  action  upon  the  organism  of  atmospheric  and  telluric 
circumstances  in  exalting  or  depressing  the  vital  resistance,  but 
strenuously  denies  the  direct  causation  of  specific  infectious  dis- 
eases by  such  obscure  or  occult  influences. 


DANGER  FROM   THE   HUMAN   BREATH  359 

§  9.  —  The  Belief  in  Dangers  from  Damp  Cellars 

It  has  long  been  accepted  as  a  fact  by  the  more  intelligent  of 
the  human  race  that  damp  cellars  are  unwholesome  abodes,  but 
the  precise  reason  for  this  belief,  other  than  the  simple  results  of 
experience,  has  always  been  hard  to  discover.  When  the  germ 
theory  of  disease  became  prominent,  it  was  felt  by  many  that  the 
solution  of  this  problem  was  at  hand,  for  what  more  favorable 
place  for  the  growth  of  germs  than  damp,  dark  cellars,  known  to 
be  inhabited  by  moulds,  and  presumably  therefore  the  favorable 
habitat  of  innumerable  other  micro-organisms? 

Investigation,  however,  has  not  tended  to  confirm  this  theory,  for 
the  air  of  cellars,  at  least  of  quiet  cellars,  is  practically  germ  free, 
while  upon  their  walls  and  floors  there  is  often  sufficient  dampness 
to  keep  any  germs  which  may  exist  there  from  rising  into  the  air. 
The  truth  appears  to  be  rather  that  certain  depressing  physiologi- 
cal or  constitutional  effects  are  produced  upon  the  human  organism 
by  the  conditions  which  prevail  in  damp  cellars,  and  that  these 
are  efficacious  in  the  production  of  specific  disease  only  by  virtue 
of  such  depression,  which  lowers  the  vital  resistance  and  increases 
the  susceptibility  to  specific  disease  germs  derived  from  any  source 
whatsoever.  The  whole  subject,  nevertheless,  undoubtedly  requires 
further  elucidation. 

It  is  interesting  to  note,  in  passing,  that  under  the  Public 
Health  Act  of  1875,  Section  41,  new  cellar  dwellings  were  pro- 
hibited, and  old  ones  regulated,  in  England  and  Wales. 

§  10.  —  The  Belief  in  Dangers  from  Human  Breath 

One  of  the  greatest  blessings  of  the  germ  theory  of  disease 
has  been  the  allaying  of  the  fears  of  mankind  in  respect  to  the 
dangers  lurking  in  human  breath.  Formerly  the  bedside  of  an 
infected  patient  was  shunned  as  a  place  of  extreme  danger,  largely 
because  the  breath,  which  seemed  to  be  the  very  essence  alike  of 
the  patient's  life  and  of  his  disease,  was  believed  to  be  loaded  with 
infection,  so  that  all  who  came  within  its  reach — and  that  meant, 
of  course,  within  the  apartment  occupied  by  the  patient  —  were 
exposed  to  the  gravest  dangers.  Bacteriology,  however,  has 
largely  done  away  with  this  dread,  for  it  has  actually  demon- 


360  APPENDIX 

strated  the  amazing  fact  that  the  expired  breath  of  the  ordinary 
human  being  is  practically  germ  free.  The  reason  for  this  appears 
to  be  that  the  inspired  air  is  not  only  drawn  in  through  narrow 
and  moist  passages,  more  or  less  lined  with  filtering  hairs  and 
projections  which  cause  the  current  of  air  to  impinge  upon  moist 
surfaces,  but  is  also  passed  through  and  over  porous  tissues  satu- 
rated with  moisture  by  which  any  micro-organisms  suspended  in 
the  air  are  retained.  It  is  still  true  that  a  patient  in  a  fit  of 
coughing  or  very  hard  breathing  may  throw  off  particles  of  sputa 
containing  disease  germs ;  but  it  is  also  true  that  the  principal  rea- 
son for  dreading  contact  with  the  human  breath,  namely,  because 
it  conveys  contagion,  is  now  done  away. 

If  it  be  asked  what  becomes  of  the  micro-organisms  thus 
detained  within  the  lungs  and  on  the  respiratory  passages,  the 
answer  probably  is  that  they  are  slowly  swept  upward  by  the 
cilia  lining  the  bronchi  and  trachea,  until  finally,  arriving  in 
the  mouth,  they  are  either  swallowed  and  pass  downward  into 
the  alimentary  canal,  or  else  discharged  as  expectoration  or  other- 
wise from  the  mouth  or  nose. 


§  II. —  The  Probable  Truth  about  Danger  from  Putrefac- 
tion and  Decay 

Much  is  heard  about  the  dangers  of  foods  spoiled  or  partially 
decomposed,  especially  because  these  processes  are  popularly  sup- 
posed to  give  rise  readily  to  the  production  of  poisonous  chemical 
bodies  roughly  classed  as  "ptomaines."  Fortunately,  most  food 
which  is  undergoing  putrefaction  and  decay  is  not  appetizing, 
and  is,  therefore,  sedulously  avoided.  On  the  other  hand,  certain 
cheeses,  butter,  and  other  food  materials  are  normally  partially 
decomposed  or  "ripened"  by  bacteria.  The  truth  appears  to 
be  that  in  rare  cases  products  may  be  formed  by  the  presence 
of  dangerous  bacteria,  which  are  really  prejudicial,  or  even  poison- 
ous, to  the  human  organism,  but  that  such  bodies  are  not  formed 
or  met  with  nearly  as  often  as  popular  rumor  would  lead  one  to 
suppose.  In  a  certain  number  of  cases  the  poisoning,  if  certainly 
present,  is  due  to  mineral  matters,  such  as  salts  of  lead,  or  tin,  or 
copper,  and  not  to  organic  poisons  of  any  kind. 


DANGERS   FROM   SPECIAL  FOODS   AND  DRINKS      361 

§  12. —  Spoiled  Meats 

The  dangers  from  spoiled  meat  are  probably  comparatively 
slight,  at  least  broadly  speaking,  because  meat  which  is  so  spoiled 
as  to  be  dangerous  is  generally  distasteful.  Nevertheless,  it  is 
possible  that  canned  or  preserved  meats,  or  meats  which  have 
been  too  much  decomposed  before  cooking,  do  occasionally  give 
rise  to  serious  trouble. 

§  13. — Ice-cream  Poisoning 

Numerous  cases  are  on  record  in  which  persons  have  suffered 
severely  after  eating  ice-cream.  In  some  of  these  cases  mineral 
poisons  are  to  be  regarded  as  the  probable  source  of  trouble,  hav- 
ing found  their  way  in  either  with  the  materials  used  for  flavoring, 
or  from  uncleanness  in  the  freezers,  or  from  other  sources  unknown. 
Rarely,  it  may  be  that  the  milk  or  cream  employed  has  contained 
organisms  capable  of  producing  harmful  fermentations ;  but  while 
it  is  generally  assumed  that  these  cases  are  true  cases  of  ptomaine 
poisoning,  much  uncertainty  exists  as  to  the  facts.  It  is  easy  for 
a  physician,  or  for  any  one,  called  to  see  patients  suffering  after 
having  eaten  ice-cream,  or  similar  foods,  to  pronounce  an  opinion 
that  the  case  is  one  of  ptomaine  poisoning.  The  more  cautious 
student  of  sanitary  science  will,  however,  require  considerable  evi- 
dence before  finally  concluding  that  such  is  the  case,  for  he  will 
remember  that  typhoid  fever  in  cities  has  often  been  erroneously 
attributed  to  ice,  to  water  and  to  various  other  sources,  when  in 
reality  it  was  due  perhaps  to  none  of  the  alleged  causes,  but  to  some- 
thing totally  different  and  unsuspected,  as,  for  example,  milk,  and 
in  other  cases  was  not  even  typhoid  at  all,  but  perhaps  trichinosis. 

§  14.  —  Canned  Foods 

All  that  has  been  said  in  §  9,  10,  n  applies,  with  equal  force,  to 
canned  foods  alleged  to  be  the  causes  of  disease.  Unquestion- 
ably these,  if  imperfectly  sterilized,  may  be  spoiled  and  contain 
living  micro-organisms.  It  is  quite  possible  that  in  certain  cases 
nausea  or  even  severe  poisoning  has  been  caused  by  the  use  of 
such  foods,  owing  to  poisonous  products  of  decomposition  present 


362  APPENDIX 

in  them.  As  a  rule,  however,  the  senses  of  taste  and  smell  in 
such  cases  may  be  depended  upon  for  warning ;  and  the  processes 
employed  in  canning,  and  the  conditions  of  unfavorable  environ- 
ment which  they  furnish  to  disease  germs,  must  be  sufficient,  in 
the  great  majority  of  cases,  to  cause  the  destruction  of  these  more 
specific  micro-organisms.  This  subject  has  already  been  dwelt 
upon  at  some  length  (p.  331). 


INDEX 


Aerobioscope,  113. 

./Etiology,  21. 

Agar-agar,  for  cultivation  of  bacteria,  54. 

Age,  old,  5,  6. 

Air,  microbes  of,  113. 

Alcohol,  as  product  of  fermentation,  38. 

as  toxin,  57. 
ALLBUTT,  T.  C.,  70. 
Amherst  College,  typhoid  fever  from  raw 

oysters,  304. 
Animalcules,  47,  48. 
Anopheles,  as  vehicle  of  malaria  germs, 


\  95.  96. 

Anthrax,  50. 
\  Antisepsis,  121,  327,  334. 

VAntiseptics,  326,  327. 
\~T\ntitoxic  serums,  83,  84,  86. 

^ 


Antitoxin,  85,  86,  94,  325. 

Arts,  the  sanitary,  19. 

Asepsis,  121,  311,  312,  326,  334. 

Aseptic  surgery,  45. 

Asiatic  cholera.     See  Cholera. 

Atmosphere,  the,  as  a  vehicle  of  disease, 

112. 
AVICENNA,  28. 


'Bacillus,  55,  56. 
-1  Bacillus,  the  typhoid,  168. 
Bacteria,  47,  48,  55.  % 

disappearance  of,  in  sewage  disposal, 
160,  161. 

discovery  of,  53. 

in  soil,  135. 

thermophilous,  133. 
Bacteriology,  establishment  of,  53. 

foundation  of,  49. 

methods  of,  54. 
BAKER,  SIR  GEORGE,  78,  79. 
BAKER,  M.  N.,  156. 
BASSI,  32. 

BEHRING,  83,  101, 325. 
BELL,  OSWALD,  264. 
Board  of  Health,  State,  of  Mass.,  140, 
142. 


Breath,  human,  not  a  vehicle  of  disease, 

359- 

BRIEGER,  59. 

BUDD,  DR.  WILLIAM,  115,  354,  355. 
Burlington,  Vt,  sewage  disposal  in,  132. 

water  supply  of,  234. 
BURDON-SANDERSON,  257. 
BURNETT,  DR.  WALDO  IRVING,  48. 

Canning,  sanitary  aspects  of,  331. 
Caterham,  England,  typhoid  in,  191,  197. 
Cellars,  unfit  human  abodes,  359. 
CHAPIN,  DR.  C.  V.,  343. 
Chlorine,  normal,  213. 
-•  'Cholera,  Asiatic,  epidemic  of,  in  London 

(1854),  170,  180. 
in  Hamburg,  Germany^gi^. 
in  London  (1866),  ,182,  183. 
its  germs  and  their  action,  169,  170. 
method  of  infection  in,  97,  98. 
microbe,  discovery  of,  56. 
Cleanness,  the  philosophy  of,  117. 
COHN,  FERDINAND,  48,  52,  54. 
T^old,  antiseptic  value  of,  328. 
'  ^Consumption,  not  inherited,  356. 
CONN,  H.  W.,  208. 
Contact  filters,  159,  163. 
Contagion,  90,  101,  116. 
Cookery,  sanitary  significance  of,/ 118, 

310. 

Corpuscles,  white,  of  blood,  100. 
~\  Cow-pox,  79,  80. 


Cremation,  341. 
Cultures,  liquid,  52-55. 

pure,  52. 

solid,  53. 
Cups,  communion,  120. 

drinking,  pollution  of,  119, 120. 

Death,  5,  8. 

causes  of,  8,  9,  10. 
Demonic  theory  of  disease,  22. 
Desiccation,  sanitary  aspects  of,  329. 
Diarrhoea,  caused  by  water  supply,  217. 


363 


364 


INDEX 


Diarrhoeal  diseases,  conveyed  by  other 
agencies  than  drinking  water, 
225. 

DlBDIN,  159,  163. 

DIMSDALE,  on  inoculation  for  small-pox, 
\  80-82. 

Diphtheria,  83,  84,  97,  100. 

microbe,  discovery  of,  56. 
Dirt,  danger  from,  117. 

derivation  of  term,  108,  109,  no. 
disposal  of,  120,  121. 
Disease,  belief  in  atmospheric  causes  of, 

358. 

biological  significance  of,  69. 
definition  of,  22. 
causes  of,  21-36. 
endemic,  357. 
infectious,  its  relation  to  parasitism, 

63-65- 
supposed  spontaneous  generation  of, 

116. 
the  principal  nominal  agent  of  death, 

9- 
Diseases,  contagious,  106. 

constitutional,  n. 

diarrhceal,  105. 

environmental,  12,  13. 

eruptive,  105,  113. 

extrinsic,  mainly  preventable,  13,  14. 

infectious,  90,  104,  113,  117. 

intrinsic,  due  to  defective  vital  ma- 
chinery, II,  12. 

not  caused  by  odors,  353,  354,  355. 

popular  beliefs  concerning  causes  of, 

347.  348.  349- 

zymotic,  117. 
Disinfectants,  special,  341,  342. 

vs.  antiseptics,  327,  334. 
Disinfection,  121,  123,  334. 

by  biological  agencies,  339. 

by  chemical  agencies,  335. 

by  mechanical  agencies,  338. 

by  physical  agencies,  336,  337. 

intestinal,  343. 

present  state  of  the  art,  343. 
Disposal  of  the  dead,  sanitary  aspects  of, 

339-  340. 

Drainage  Commission,  Mass.,  139-141. 
Drainage,  definition  of,  124,  125. 
Drains,  broken,  belief  in  danger  from, 

352- 

DROWN,  THOMAS  M.,  157,  213,  258. 
V     Dry-earth  system,  123. 
\  Dust  and  disease,  in. 
^Dysentery,  from  drinking-water,  217. 


Earth,  as  a  vehicle  of  disease,  109,  no, 
in. 

the  living,  no,  127,  134,  135,  137. 
Earthworms,  109,  135,  136. 
EBERTH,  56. 
EDDY,  H.  P.,  156. 
EDWARDS,  JONATHAN,  80. 
Effluents,  sewage  from  filters,  161. 
EHRENBERG,  48. 
Electrical    purification    of    water    and 

sewage,   157. 
Environment,  67-74,  Io°- 

sources  of  infectious  material  in,  103. 
Environmental  diseases,  12. 
Epithelia,  as  defences,  91,  92. 

as  portals  of  infection,  93,  94,  97. 
Excrement,  108. 
Excreta,  disposal  of,  123,  124, 125,  126. 

as  vehicles  of  disease,  105,  106, 107. 
Experiment  Station,   Lawrence,   Mass., 
142. 

FARR,  WILLIAM,  36, 56,  94, 103. 

Favus,  13,  33,  66. 

Fermentation,  and  disease,  38,  39. 

germ  theory  of,  36,  37,  40. 

in  Asiatic  cholera,  98. 
Ferments,  how  they  produce  disease,  56. 
Ferment-poison  theory  of  disease,  58. 
Filter,  municipal,  for  sewage,  at  Brock- 
ton, Mass.,  146. 

at  Framingham,  Mass.,  146. 
Filters,  contact,  159,  163. 

municipal,  for  water,  238. 

tests  of  rapid  mechanical,  for  water, 

240. 
Filter-tanks,  experimental,  at  Lawrence, 

Mass.,  144. 

Filth,  vehicle  rather  than  source  of  dis- 
ease, 117. 

Filth  diseases,  114.  116. 
Filtration.  See  also  I  nterm  ittent  Filtration. 

intermittent,  143-149. 

value  of,  in  water-supply,  187. 
Fire,  as  a  disinfectant,  121. 
Flies,  as  vehicles  of  disease,  96. 
Food,  uncooked,  as  vehicle  of  disease, 

118,  293. 

Formaline,  as  disinfectant,  342. 
Fountains,  sanitary,  120. 
Fruits,  as  vehicles  of  disease,  308,  309. 
FULLER,  GEORGE  W.,  240. 

GAFFKY,  56. 
GALEN,  27. 


INDEX 


365 


Garbage,  120, 121. 
Germs,  47. 

zymotoxic  action  of,  60. 
Germ  theory,  36,  37,  112. 

objections  to,  60,  61. 
Germicides,  their  efficiency,  342. 
Ground  water,  226. 

conservation  of  purity  of,  229. 

pollution  and  purification  of,  226,  227, 
228. 

HAGLER,  190,  191. 
HAHNEMANN,  30. 
Harbors,  sewage  disposal  in,  130. 
HART,  ERNEST,  265. 
HAZEN,  ALLEN,  156,  218,  240. 
Health,  definition  of,  4. 

in  terms  of  general  biology,  69. 
HILL,  HlBBERT  W.,  262. 

HlPFOCRATES,  26,  27. 

Human  body,  as  a  mechanism,  3-5,  8, 

67,  69,  70. 
Human  breath,  as  a  vehicle  of  disease, 

359- 

Humors,  the  four,  theory  of,  26. 
Hygiene,  definitions  of,  17,  18,  19. 

functions  of,  13,  14,  15,  16. 

personal,  15,  19. 

public,  15,  18. 
Hygiology,  definition  of,  19. 

Ice,  as  vehicle  of  infectious  disease,  251, 

258,  262. 
epidemics  attributed  to,  254,  255,  256. 

\its  purity  investigated,  257,  258. 
Ice  supply,  and  the  public  health,  262. 
Immunity,  75,  81,  83,  99,  315,  316,  324, 
\  326. 

•^Immunization,  process  of,  83,  84. 
Infection,  90,  91. 

by  fruits,  vegetables,  ice-cream,  etc., 

308,  309. 

by  tuberculous  meats,  297. 
^*—  by  way  of  the  skin,  or  by  wounds,  92, 

93.  94- 
by  way  of  the  throat,  alimentary  canal, 

etc.,  96,  97,  98. 
control    of,    in    decomposition    and 

decay,  327. 
danger  of,  from  raw  shell-fish,  305, 

306. 
of  vegetables  and  small  fruits,  153, 

154- 

of  water-supply  in  London  epidemic 
of  1866,  184-186. 


prevention  of,  by  exclusion,  311,  313, 
314- 

prevention  of,  by  insusceptibility,  315. 

primary  sources  of,  103,  104,  105,  106. 
Infectious  diseases,  67. 
Inheritance,  importance  of,  in  sanitary 

science,  8. 
Inland  waters,  pollution  of,  139. 

protection  of,  141. 
'Inoculation,  76,  78. 
.."  for  anthrax,  321. 
s~  for  small-pox,  77,  316,  317. 
s~  of  antitoxin  for  diphtheria,  86. 

objections  to,  317. 

of  tuberculosis,  277. 
Insects,  as  vehicles  of  disease,  94. 
Insusceptibility  to  disease,  produced  by 
inoculation,  316. 

by  antitoxins,  325. 

by  vaccination,  318,  319. 

the  goal  of  sanitary  science,  315. 
Interment  w.  cremation,  341. 
Intermittent  filters,  anatomy  and  physi- 
ology of,  145. 
Intermittent  filtration,  136-138. 

English  experiments  on,  137,  138. 

Massachusetts  experiments  on,  143. 

not  mechanical,  but  biological,  147, 
148. 

objections  to,  148. 

theoretical  aspects  of,  146,  147. 
Isolation,  or  local  quarantine,  313. 

JENNER,  80,  317,  318,  320. 

KERNER,  58,  59. 
KINNICUTT,  LEONARD  P.,  159. 
KIRCHER,  47,  53. 
KOCH,  ROBERT,  49-56,  60,  356. 

Lakes,  sewage  disposal  in,  129,  130,  132. 

LATOUR,  CAGNIARD  DE,  35. 

Lausen  (Switzerland),  typhoid  fever  in, 

187-189. 

Lawrence,  Mass.,  Experiment  Station, 143. 
Lawrence  and    Lowell,   Mass.,   typhoid 

fever  in,  211. 

LEEUWENHOEK,  47,  48,  53. 
LEIDY,  JOSEPH,  257. 
Leucomaines.,  59. 
LIEBIG,  33,  34,  36,  50. 
Life,  definition  of,  69. 

three  principal  sanitary  conditions  of, 

70. 
LISTER,  SIR  JOSEPH,  45,  54. 


366 


INDEX 


LOCKE,  JOHN,  29. 

London,  cholera  in  Broad  Street,  170^ 

173-177. 
Broad  Street  well,  description  of,  179, 

180. 
Lowell  and    Lawrence,   Mass.,  typhoid 

fever  in,  211,  212,  213. 


MILLS,  HIRAM  FRANCIS,  140,  143,  212. 
MONTAGU,   LADY   MARY   WORTLEY, 

76,  316. 

^Mosquitoes,  as  carriers  of  disease,  94. 
as  carriers  of  malaria,  94,  95,  106. 
MURCHISON,  114,  115. 
Muscardine,  32,  66. 


"^Malaria,  and  mosquitoes,  94,  95,  106. 

not  due  to  bad  air,  114. 
Massachusetts,    experiments    on    inter- 
mittent nitration,  143. 
McCOLLOM.  DR.  J.  H.,  on  antitoxins,  86. 
Metschnikoff,  82,  83. 
\    Miasms,  103,  104,  112. 
Micro-organisms,  48,  49. 

cause,  not  consequence  of  disease, 

So,  Si- 

infectious,  fate  of,  in  sewage  purifica- 
tion, 162. 

Microbes,  definition  of,  48. 
Milk,  as  food  for  microbes  and  mankind, 

263. 

as  a  germicide,  100. 
as  soil  for  bacteria,  100. 
as  a  vehicle  of  infectious  disease,  253, 

254- 

as  a  cause  of  infants'  diseases,  267. 

condensation  of,  as  a  sanitary  safe- 
guard, 288,  332. 

diphtheria  in,  278. 

fermentation  of,  265,  266.  \ 

infected  by  pus,  284. 

modified,  289. 

normal,  definition  of,  269. 

normal  vs.  fermented,  266,  267. 

pasteurization  of,  287,  332. 

scadet  fever  in,  278. 

sterilization  of,  286.   . 

the  pollution  of,  267,  268. 

tuberculosis  in,  276. 
Milk  (dairies),  sanitary,  290,  291,  292. 
Milkers,    requirements    of,    in    modern 

dairies,  291. 
Milk  supplies,  119,  121,  122. 

epidemics  of  typhoid  fever  in  Mass. 
traced  to,  273. 

infection  of,  by  cows,  282,  283. 

infection  of,  by  man,  279. 

in  hot  countries,  272. 

protection  of,  from  infection,  279,  280, 
281,  285. 

protection  of,  from  pollution,  278,  279, 
285. 

systems  of,  268,  269,  270,  271. 


NAGELI,  48. 
NEISSER,  94. 
NENCKI,  59. 
Nitrification,  in  sewage  purification, 

137- 
Normal  chlorine,  213. 

Odors,  offensive,  not  necessarily  inju- 
rious, 353,  354. 

One-Hoss  Shay,  6,  7. 

ORD,  DR.,  355. 

Organism,  definition  of,  68. 

Oysters,  raw,  as  vehicles  of  disease,  297, 
298,  299,  304,  3°7- 

Ozone,  158. 

Paludism,  114. 

PANUM,  59. 

Parasite,  definition  of,  64,  65,  66. 

Parasitism,  its  relation  to  infectious  dis- 
ease, 63,  64,  65. 

Particulate  theory,  66. 

PASTEUR,  Louis,  37,  40, 41, 45,  48, 49, 52, 
53,  81,  82,  159,  320,  321. 

Pasteurizing,  of  foods,  sanitary  aspects 
of,  332. 

Phagocytes,  83,  84,  100,  101. 

Phagocytosis,  a  theory  of  immunity,  83, 

100. 

Pickling,  sanitary  aspects  of,  331. 
Plymouth  (Penn.),  epidemic  of  typhoid 

in,  1885,  200-205,  25S' 
Poisoning,  from  foods  and  drinks,  360, 

361. 

Pollution  vs.  infection,  213,  214. 
Ponds,  sewage  disposal  in,  129,  130. 
Preserving,  sanitary  aspects  of,  330. 
Preventive  medicine,  10. 
PRUDDEN,  T.  M.,  112, 252,  257. 
Ptomaines,  59,  360,  361. 
Public  health,  definition  of,  18. 
Public  supplies  as  public  dangers,  221, 

222. 
Public  water  supplies,  purity  in,  221-223, 

242. 
Purification  of  sewage  and  of  water.    See 

Sewage,  and  Water. 


INDEX 


367 


Putrefaction,  probable  truth  about,  360. 
Pythogenic  theory,  114,  115. 

Quarantine,  313,  314. 

QUATREFAGES,  44. 

RADCLIFFE,  J.  N.,  178,  182, 183. 
Rain  water,  pollution  of,  by  dust,  224. 
pollution  of,  by  the  earth,  225,  226. 
Refrigeration,  sanitary  aspects  of,  328. 
Refuse,  disposal  of,  120. 
Reservoirs,  purification  of,  by  stripping, 

241. 

Resistance,  vital,  74,  99. 
Rivers,  sewage  disposal  in,  127,  128,  131. 
Rivers  Pollution  Commission,  148,  154, 

iS5,  167- 

ROCKWELL,  DR.  JOHN  A.,  113. 
ROECHLING,  H.  A.,  349. 

ROLLESTON,  352. 

Roux,  101,  325. 

Sands,  kinds  of,  adapted  for  filtration 

146. 

Sanitary  science,  definitions  of,  15, 19. 
.  Sanitation,  function  of,  15. 

requires  expert  supervision,  250. 
Saprophytes,  65. 
Saprophytism,  64. 
•^Scarlet  fever  in  milk,  264,  278. 
Schizomycetes,  48. 

SCHOENLEIN,  33. 
SCHWANN,  36. 
Sepsin,  59. 
Septicaemia,  93. 

\  Sea,  sewage  disposal  in  the,  130,  131. 
*  Serum,  84,  85. 

as  cure  and  as  prevention,  84. 
Serum  therapy,  325. 
Sewage,  as  vehicle  of  disease,  123,  126. 

as  fertilizer,  150,  151,  152,  153. 

composition  and  properties  of,  125, 
126. 

dangerous  elements  of,  126. 

definition  of,  124. 

disposal  of,  126-131,  136,  138. 

disposal  of,  by  electricity,  156. 

disposal  of,  by  fermentation  or  putre- 
faction, 158,  159. 

disposal  of,  by  irrigation,  149-153. 

disposal  of,  on  land,  experiments  on, 

143. 144- 

disposal  of,  by  septic  process,  158. 
farms,  152,  153. 
genesis  of,  124,  125. 


importance  of  sanitary  disposal  of, 
126,  127,  159-162. 

infection  of,  by  typhoid  and  cholera 
germs,  168,  170. 

oxidization  of,  152. 

purification  of,  124,  129,  132,  134,  135, 
137. 

purification  of,  by  chemical  precipita- 
tion, 154,  155,  156. 

purification  of,  by  dilution,  160. 

purification  of,  by  electricity,  156,  157, 
158. 

purification  of,  by  irrigation,  150,  151. 

theory  of  self-purification  of,  128. 

valuable  ingredients  of,  154. 
Sewerage,  definition  of,  124,  125. 
Sewer-gas,  347,  348,  349. 
Shay,  the  One-Hoss,  6,  7. 
Silkworm  disease,  description  of,  41-44. 
SIMON,  SIR  JOHN,  182. 
Skin,  the,  as  defence  against  infection, 
9L  92. 

as  portal  of  infection,  93,  95,  96. 
iSmall-pox,  38,  39,  76-79. 
SMITH,  THEOBALD,  75. 
Smoking,  sanitary  aspects  of,  330. 
SNOW,  DR.  JOHN,  173,  175,  176,  177. 
Snow,  pollution  of,  and  by,  224,  225. 
Soil,  108,  109. 
Spirillum,  56,  169. 
Splenic  fever,  50. 

Sporadic  cases  of  typhoid  fever,  309. 
Sterilized  milk,  287. 
Streams,  self-purification  of,  128,  231. 
Struggle  for  existence,  sanitary  aspects 

of,  62,  63,  72,  74. 
Surface-waters,  226,  230. 

conservation  of  purity  of,  240,  241. 
Survival  of  the  fittest,  73. 
Susceptibility,  natural,  74,  324. 

the  sanitary  meaning  of,  74,  99,  100. 
SYDENHAM,  THOMAS,  29. 
SYLVIUS,  28. 


,  95. 

TAYLOR,  DR.  L.  H.,  200. 
TAYLOR,  DR.  MICHAEL,  264. 
'Tetanus,  56,  94,  104,  no. 
THACKRAH,  353. 

n£THORNE-THORNE,  DR.,  191,  194,  195. 
[Toxin,  57,  59,  67,  97,  324. 

Trichina,  103,  293. 

Trichinosis,  66,  293,  294,  295. 
epidemics  of,  296. 

Tuberculin,  283. 


368 


INDEX 


-*  Tuberculosis,  discovery  of  bacillus  of,  55. 

in  milk,  276. 
TUCKER,  G.  R.,  113. 
^  TYLOR,  E.  B.,  22. 

Typhoid  fever,  167. 
^^-^jacillus  of,  168. 

x-  epidemic  of,  due  to  impure  water,  187, 
/  188,  189. 

epidemic  of,  in  Lausen,  Switzerland, 

in  1872,  187. 
epidemic  of,  in  Caterham,  England, 

191,  192,  193,  194. 
epidemic  of,  in  New  Haven,  Conn., 

216. 
epidemic  of,  in  Plymouth,  Penn.,  200, 

201. 
epidemic  of,  in  Red  Hill,  England, 

193.  !94- 
epidemic  of,  traced  to  infected  oysters, 

298-303. 
^-""epidemics    of,    traced    to    skimmed 

milk  and  creameries,  275. 
in  Cambridge,  Mass.,  274. 
in  Chicago,  218. 

in  cities  on  the  Merrimac  River,  207. 
in  Lowell  and  Lawrence,  Mass.,  211- 

214. 

in  Marlborough,  Mass.,  275. 
in  Newburyport,  Mass.,  214,  215. 
in  Somerville,  Mass.,  274. 
in  Springfield,  Mass.,  273. 
not  a  pythogenic  fever,  115. 
viability  of  the  bacillus  of,  104. 
• !  Typhus  fever,  116,  320. 

distinction  from  typhoid,  167. 

J 

Vaccination,  for  small-pox,  80,  319. 

for  anthrax,  by  Pasteur,  324. 
Vegetables,  as  vehicles  of  disease,  308, 

309- 

Vibrio,  56,  169. 

Vibrionia,  48. 

Vital  Resistance,  74,  75,  98,  99. 

Water.    See  also  Water  Supply. 

as  a  vehicle  of  infectious  disease,  164, 

165. 
as  a  vehicle  of  diarrhoea!  diseases, 

166. 


Water,  natural  processes  of  purification 

of,  233. 
purification  of,  by  freezing,  12, 52, 253, 

254- 
quiet,  not  running,  is  self-purifying, 

160,  233. 

self-purification  of,  231,  232. 
sewage-polluted,    a    vehicle,    not    a 

source,  of  infectious  disease,  214, 

215- 

Waters,  natural  or  pure,  165. 

protection  of  inland,  in   Mass.,  243, 

244. 

Water-carriage  system,  123,  124. 
Watersheds,  sanitary  protection  and  in- 
spection of,  246,  247,  248,  249. 
Water  supply,  atmosphere  as  source  of, 

223. 
epidemic  of  cholera  traced  to  infected, 

182. 

of  Burlington,  Vt.,  234. 
purification  of,  by  dilution  and  quies- 
cence, 235. 

purification  of,  by  mechanical  proc- 
esses, 239. 
purification  of,  by  slow  sand  filtration, 

237,  238,  239. 

purification  of,  by  storage,  237. 
Wells,  theory  of  infection  by,  350. 
Well  waters,  belief  in  dangers  from,  349, 

350,  35i- 

WELPLY,  J.  J.,  276. 

Wesleyan  University,  typhoid  fever  epi- 
demic from  raw  oysters  in,  298- 

303- 

WHITEHEAD,  REV.  H.,  and  Broad  Street 
pump,  177,  178,  181. 

WlDAL,  serum  test  of  typhoid,  169. 

WlNSLOW,  C.  E.  A.,  251,  259. 

Worcester,  Mass.,  experiments  on  chemi- 
cal precipitation,  156. 

Wounds,  diseases  of,  93,  94. 

Yellow  fever,  96. 
YORK,  J.,  179. 

Zymotic,  origin  of  word,  35. 

diseases,  34,  35,  36,  62. 
Zymotoxic  theory,  56,  58, 59,  60,  222,  223. 


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